Mary E. Barkworth
Julian J.N. Campbell
Bjorn Salomon
Plants perennial; sometimes cespitose, with or without rhizomes, sometimes stoloniferous. Culms 8180(220) cm, usually erect to ascending, sometimes strongly decumbent to prostrate, usually glabrous. Leaves usually evenly distributed, sometimes somewhat basally concentrated; sheaths open for most of their length; auricles often present; ligules membranous, truncate or rounded, sometimes acute, entire or erose, often ciliolate; blades 124(25) mm wide, abaxial surfaces usually smooth or scabrous, sometimes with hairs, adaxial surfaces scabrous or with hairs, particularly over the veins, usually with unequal, not strongly ribbed, widely spaced veins, sometimes with equal, strongly ribbed, closely spaced veins. Inflorescences spikes, usually exserted, with 13(5) spikelets per node, internodes (1.5)226 mm; rachises with scabridulous, scabrous, or ciliate edges. Spikelets usually appressed to ascending, sometimes strongly divergent or patent, with 111 florets, the distal florets often reduced, the lowest florets usually functional, sterile and glumelike in some species; disarticulation usually above the glumes and beneath each floret, sometimes also below the glumes or in the rachises. Glumes usually 2, absent or highly reduced in some species, usually equal to subequal, sometimes unequal, usually linear-lanceolate to linear, setaceous, or subulate, sometimes oblanceolate to obovate, (0)17-veined, sometimes keeled over 1 vein, not necessarily the central vein, the keel vein sometimes extended into an awn; lemmas linear-lanceolate, obscurely 5(7)-veined, apices acute, often awned, sometimes bidentate, teeth to 0.2 mm, sometimes with bristles, bristles to 10 mm, awns terminal or from the sinus, straight or arcuately divergent, not geniculate; paleas from shorter than to slightly longer than the lemmas, keels scabrous or ciliate, at least in part; anthers 3, 0.77 mm. Caryopses with hairy apices. x = 7. Haplomes St, H, Y, P. Name from the Greek elyo, rolled up, the caryopses being tightly embraced by the lemma and palea.
As interpreted here, Elymus is a widespread, north-temperate genus of about 150 species. It includes Sitanion Raf. and Roegneria K. Koch, but moves some taxa that others include in Elymus to Leymus , Pascopyrum , Pseudoroegneria, and Thinopyrum. [Recently (Barkworth 2009), I agreed with Yen et al. in adopting a narrower interpretation of the genus. That would move Elymus ciliaris to Roegneria ciliaris and and , in which Roegneria and Thirty-two species of Elymus are native to the Flora region. Of the seven non-native species treated, one is established (E. repens ), two are distributed as forage (E. dahuricus and E. hoffmannii ), two are known from ballast dumps and are not established (E. tsukushiensis and E. ciliaris ), and two (E. caninus and E. semicostatus ) have been attributed to the Flora region but specimens documenting the reports have not been located. Eight named, naturally occurring, intrageneric hybrids are described at the end of the treatment. They are not included in the key. As mentioned in the descriptions of the non-hybrid species, other interspecific hybrids undoubtedly exist. Because many of the hybrids are partially fertile, backcrossing and introgression occurs. Intergeneric hybrids are treated under ΧElyhordeum, ΧElyleymus , ΧPascoleymus, ΧPseudelymus , and ΧTriticosecale; most are sterile.
The complex patterns of morphological diversity within Elymus in
All species of Elymus are alloploids that combine one copy of the St haplome present in Pseudoroegneria with at least one other haplome. So far as is known, all species that are native to North America, as well as many species native to northern Eurasia, are tetraploids with one additional haplome, the H genome from Hordeum sect. Critesion . Many Asian species combine the St haplome with the Y haplome, for which there are no known diploids; such species are sometimes placed in the segregate genus Roegneria. This treatment includes two such species, E. ciliaris and E. semicostatus. In addition, the treatment includes two hexaploid species, E. tsukushiensis and E. dahuricus, that combines all three haplomes. Elymus repens and E. hoffmannii, the other two hexaploid species in this treatment, basically combine two copies of the St haplome with one of the H haplome, but the molecular data for E. repens point to a more complex situation (Mason-Gamer 2001). For further discussion of generic delimitation in the Triticeae, see Barkworth (2000), Yen et al. (2005), and Barkworth and von Bothmer (2005).
Elymus is sometimes divided into multiple sections (see, for example, Tsvelev 1976; Lφve 1984). There are, however, no detailed morphological descriptions of the sections, making it difficult to determine how to treat the North American species. It is notable that the species with solitary spikelets are concentrated in western and northern North America, whereas the species with multiple spikelets at a node are most prevalent east of the Rocky Mountains, from southern
In the key and descriptions, unless otherwise stated, the following conventions are observed: the number of culm nodes refers to the number of nodes above the base; measurements of spikes include the awns, while measurements of spikelets, glumes, and lemmas do not; rachis internodes are measured in the middle of the spike; glume widths of lanceolate to linear glumes are measured at the widest point, and those of linear to setaceous glumes about 5 mm above the base of the glumes; the number of florets in a spikelet includes the distal reduced, sterile florets; and dates of anthesis, when provided, are for the central range of each species.
The curvature of the lemma awns is often important in identifying individual species. The curvature increases with maturity, and may vary within a spike. If a plant appears to have at least some strongly curved lemma awns, it should be taken through the strongly curved side of the key.
SELECTED REFERENCES
1. Spikelets 1 at all or most nodes; glumes with flat, non-indurate bases, glume bodies linear-lanceolate to obovate, margins hyaline, scarious, or chartaceous; lemmas awned or unawned 2.
2. Anthers 37 mm long; plants often strongly rhizomatous, sometimes not or only weakly rhizomatous 3
3. At least some lemmas with strongly divergent, outcurving, or recurved awns 4
3. Lemmas unawned or with straight to flexuous awns 7
4. Culms prostrate to decumbent and geniculate, 2050 cm tall; plants of subalpine and alpine habitats 32. E. sierrae (in part)
4. Culms erect or decumbent only at the base, (15)40130 cm tall; plants of valley and montane, but not subalpine or alpine, habitats 5
5. Plants strongly rhizomatous; blades 13 mm wide 34. E. albicans
5. Plants cespitose or weakly rhizomatous; blades 1.56 mm wide 6
6. Spikes often drooping to pendent at maturity; rachis internodes 1117 mm long; plants of the southwestern United States 29. E. arizonicus
6. Spikes erect to slightly nodding at maturity; rachis internodes 512 mm long; plants of the northwestern contiguous United States 33. E. wawawaiensis
7. Lemmas 1214 mm long; plants not or weakly rhizomatous 8
7. Lemmas 7–12 mm long; plants not, weakly, or strongly rhizomatous 9
8. Palea keels straight or slightly outwardly curved below the apices, apices about 0.2 mm wide between the vein ends E. glaucus (in part)
8. Palea keels distinctly outwardly curved below the apices; apices 0.30.7 mm wide between the vein ends 39. E. semicostatus
9. Glumes keeled distally, keels smooth and inconspicuous proximally, scabrous and conspicuous distally; lemmas glabrous 10
9. Glumes not keeled or keeled throughout their length, keels smooth or scabrous throughout, sometimes hairy, conspicuous or not 11
10. Adaxial surfaces of the blades usually sparsely pilose, sometimes glabrous, veins smooth, the primary veins separated by secondary veins; plants strongly rhizomatous.. 35. E. repens
10. Adaxial surfaces of the blades glabrous, veins smooth or scabrous, all veins more or less equally prominent; plants slightly to moderately rhizomatous................. 36. E. hoffmannii
11. Plants strongly rhizomatous; glumes 59 mm long; lemmas densely to sparsely hairy or glabrous 27. E. lanceolatus (in part)
11. Plants cespitose or weakly rhizomatous; glumes 619 mm long; lemmas glabrous or pubescent, never densely hairy 12
12. Spikelets usually at least twice as long as the internodes; internodes 412 mm long; glumes often awned, sometimes unawned; blades usually lax.... 10. E. glaucus (in part)
12. Spikelets from shorter than to almost twice as long as the internodes; internodes 927 mm long; glumes unawned; blades usually straight 28. E. stebbinsii2. Anthers 0.73 mm long; plants usually not or weakly rhizomatous, sometimes strongly rhizomatous.
13. Culms prostrate or strongly decumbent at the base; disarticulation in the rachises or beneath the florets; plants of subalpine, alpine, and arctic habitats.
14. Glumes unawned or with awns to 1 mm long; plants of arctic regions. 26. E. alaskanus (in part)
14. Glumes awned, awns 330 mm long; plants of subalpine and alpine regions.
15. Anthers 11.6 mm long; internodes 2.55(7) mm long; disarticulation initially in the rachises; spikelets appressed to ascending................................................. 31. E. scribneri
15. Anthers 23.5 mm long; internodes 515 mm long; rachises not disarticulating; spikelets ascending to divergent.................................................................. 32. E. sierrae (in part)
13. Culms usually ascending to erect, sometimes geniculate or weakly decumbent at the base; disarticulation beneath the florets; plants of sea level to subalpine habitats 16
16. Lemmas with coarse, stiff, marginal hairs up to 1 mm long; paleas 2/34/5 as long as the lemmas, with wide, rounded apices.................................................................. 38. E. ciliaris16. Lemmas with the marginal hairs, if present, similar to those elsewhere on the lemma; paleas 3/4 as long as to slightly longer than the lemmas, tapering to the apices 17
17. Lemmas awned, awns 740 mm long.18. Lemma awns strongly arcuate to outcurving or recurved.
19. Spikes 812 cm long, straight, erect or inclined; blades 24 mm wide 30. E. bakeri 19. Spikes 730 cm long, flexuous, nodding to pendent; blades 514 mm wide... 13. E. sibiricus (in part) 18. Lemma awns usually straight or flexuous, or, if shorter than 10 mm, sometimes weakly curving.20. Glumes with hairs on the adaxial (inner) surface, these often inconspicuous... 23. E. caninus
20. Glumes glabrous on the adaxial (inner) surface.
21. Palea keels distinctly outwardly curved below the apices, winged, not or scarcely extending beyond the intercostal region; apices 0.30.5 mm wide.. 37. E. tsukushiensis
21. Palea keels straight or slightly outwardly curved below the apices, not winged, often extending beyond the intercostal region, sometimes forming teeth; apices 0.10.3 mm wide.
22. Glumes 1.82.3 mm wide, margins 0.20.3 mm wide.. 22. E. trachycaulus (in part)
22. Glumes 0.41.5(2) mm wide, margins 0.10.2 mm wide.
23. Spikes erect or almost so, 0.52 cm wide......... 10.E. glaucus (in part)
23. Spikes nodding to pendent, 25 cm wide........ 13. E. sibiricus (in part)
17. Lemmas unawned or with awns up to 7 mm long.
24. Plants strongly rhizomatous.............................................. 27. E. lanceolatus (in part)
24. Plants not or only shortly rhizomatous.
25. Glumes 1/32/3 as long as the adjacent lemmas.
26. Glumes 0.81.8 mm wide, lanceolate, margins subequal; lemmas evenly hairy or glabrous distally........................................................... 25. E. macrourus
26. Glumes 1.52 mm wide, oblanceolate to obovate, margins unequal; lemmas glabrous, evenly hairy, or more densely hairy distally 26. E. alaskanus (in part)
25. Glumes 3/4 as long as to slightly longer than the adjacent lemmas.
27. Glumes 3(5)-veined; glume margins unequal, the wider margins 0.31 mm wide, usually widest in the distal 1/3; lemma awns 0.53 mm long........ 24. E. violaceus
27. Glumes 37-veined, glume margins equal, 0.10.5 mm wide, widest at or slightly beyond midlength; lemmas unawned or with awns to 40 mm long.
28. Glumes 1.82.3 mm wide, margins 0.20.3 mm wide.. 22. E. trachycaulus (in part)
28. Glumes 0.41.5(2) mm wide, margins 0.10.2 mm wide. 10. E. glaucus (in part)
1. Spikelets 23(5) at all or most nodes; glumes often with subterete to terete, indurate bases, sometimes with flat, non-indurate bases, glume bodies linear-lanceolate to setaceous or subulate, margins usually firm, sometimes hyaline or scarious; lemmas usually awned, awns up to 120 mm long.
29. Rachises disarticulating at maturity; glumes 10135 mm long including the awns, sometimes split longitudinally, flexuous to outcurving from near the base; lowest floret in each spikelet sometimes sterile; blades 16 mm wide.
30. Glume awns split into 39 divisions; lemma awns about 0.2 mm wide at the base; rachis internodes 35 mm long................................................................................. 20. E. multisetus
30. Glume awns entire or split into 23 divisions; lemma awns about 0.4 mm wide at the base; rachis internodes 310(15) mm long.......................................................................... 21. E. elymoides
29. Rachises not disarticulating at maturity; glumes 043 mm long including the awns, entire, straight or outcurving from well above the base; lowest floret in each spikelet functional; blades 225 mm wide.
31. Glume bodies with 01(2) veins, linear or tapering from the base, 0.10.6 mm wide, 024 mm long including the awns, often differing in length by more than 5 mm, persistent after the florets disarticulate; rachis internodes 0.10.3(0.4) mm thick at the thinnest sections, often with longitudinal green bands along the sides.
32. Spikelets widely divergent to patent at maturity; lemma awns usually straight, rarely slightly curving; glumes vestigial or 13 mm long, occasionally some unequal glumes up to 10(20) mm long and 0.10.2 mm wide but with no distinct vein; spikes more or less erect........ 19. E. hystrix
32. Spikelets usually appressed, never widely divergent; lemma awns straight or curving; glumes sometimes vestigial, usually 124 mm long, 0.10.6 mm wide, often with 1(2) distinct veins; spikes erect, nodding, or pendent.
33. Glumes 1230 mm long including the awns, subequal; lemma awns straight to moderately curving; spikes erect to slightly nodding.
34. Spikelets (6)915(22) mm long excluding the awns, each with 25 florets; lemma awns moderately outcurving at maturity; glumes (0.2)0.30.5(0.7)mm wide....... 9. E. interruptus (in part)
34. Spikelets 1840 mm long (excluding the awns), each with 38 florets; lemma awns straight to slightly curving at maturity; glumes 0.10.3(0.6) mm wide.
35. Anthers 2.54 mm long; lemmas scabrous-hispid to thinly strigose, at least distally; spikes 412 cm long; internodes 36 mm long, without green lateral bands, with hispid dorsal angles................................................. 14.E. pringlei
35. Anthers 4.56 mm long; lemmas smooth, glabrous; spikes 920 cm long; internodes (5)715(22) mm long, with green lateral bands, glabrous except for the ciliolate margins....................................................................... 15. E. texensis
33. Glumes 015(30) mm long including the awns, usually differing in length by at least 4 mm, 1 or both shorter than 12 mm, sometimes both essentially absent; lemma awns outcurving at maturity; spikes more or less nodding.
36. Rachis internodes 46(9) mm long; lemmas hirsute to strigose, at least near the margins, awns 2035 mm long; sheaths glabrous; plants not glaucous or moderately glaucous................................................................................. 18. E. diversiglumis
36. Rachis internodes (4)613(18) mm long; lemmas glabrous or pubescent, awns (8)1030(35) mm long; sheaths glabrous or villous; plants usually glaucous, sometimes strongly so.
37. Lemmas usually glabrous, veins occasionally hispidulous near the apices, awns (8)1020(25) mm long; spikelets with (3)45 florets; rachis internodes (4)610(12) mm long, without green lateral bands, glabrous; adaxial surfaces of the blades usually villous; plants strongly glaucous.................................... 16. E. svensonii
37. Lemmas usually hairy, awns (10)2030(35) mm long; spikelets with 3(5) florets; rachis internodes (5)713(18) mm long, with green lateral bands and hispid dorsal angles; adaxial surfaces of the blades glabrous or short-pilose; plants somewhat glaucous.................................................................................. 17. E. churchii
31. Glume bodies with 25(8) veins, widening or parallel-sided above the base, (0.2)0.32.3 mm wide, 443 mm long including the awns, equal or subequal, persistent or disarticulating; rachis internodes 0.10.8 mm thick at the thinnest sections, usually lacking green lateral bands.
37. Glume bases flat and veined or, if subterete to terete, indurate and without veins for less than 1 mm; glume bodies shorter than or subequal to the lowest lemmas; lemma awns usually flexuous to curving, sometimes straight; rachis internodes (2)314 mm long.
38. Glumes with flat bases and hyaline or scarious margins, usually awned, awns 110 mm long, sometimes unawned; spikelets (1)2(3) per node, appressed to divergent, sometimes purplish; cauline nodes mostly exposed.
39. Anthers 0.91.7 mm long; glumes 38 mm long; lowest lemmas 36 mm longer than the glumes, densely scabridulous to scabrous, awns usually outcurving; spikelets with (3)45(7) florets; spikes 25 cm wide, nodding to pendent; cauline nodes glabrous. 13. E. sibiricus (in part)
39. Anthers 1.54.5 mm long; glumes (4.5)614(19) mm long; lowest lemmas from shorter than to 2.5 mm longer than the glumes, smooth, sometimes hairy, awns straight, flexuous, or outcurving; spikelets with 24(7) florets; spikes (0.2)0.52.5 cm wide, erect, nodding, or pendent; cauline nodes occasionally with short hairs.
40. Glume bodies (6)914(19) mm long; lemmas 816 mm long, awns usually straight to flexuous; auricles usually present, to 2.5 mm long.... 10. E. glaucus (in part)
40. Glume bodies (4.5)610(11) mm long; lemmas 514 mm long, awns flexuous to moderately outcurving; auricles often absent, or to 1.5 mm long.
41. Lemmas with hairs, the marginal hairs markedly longer than those elsewhere; paleas acute; spikes nodding to pendent; rachis internodes 312 mm long; leaves usually deep green; plants native to the Pacific coastal mountains.......................................................................... 11. E. hirsutus
41. Lemmas smooth, scabrous, or hispid, the marginal hairs, if present, not markedly longer than those elsewhere; paleas obtuse or truncate; spikes erect to slightly nodding; rachis internodes 36 mm long; leaves usually pale green, sometimes glaucous; plants introduced...................... 12. E. dahuricus
38. Glumes with more or less terete bases, without hyaline or scarious margins, always awned, awns (5)825(27) mm long or the glume bodies indistinguishable from the awns; spikelets (1)23(5) per node, spreading, not or rarely purplish; cauline nodes usually concealed by the sheaths.
42. Spikes erect to slightly nodding, internodes (5)814 mm long; glumes 0.20.5(0.7) mm wide; lemmas 710 mm long, usually smooth or scabrous, occasionally hirtellous, especially near the margins, awns 1522 mm long, straight to moderately outcurving; blades 39 mm wide; culms (40)60100(120) cm tall, nodes usually exposed........................................................................... 9. E. interruptus (in part)
42. Spikes usually nodding to pendent, sometimes erect, internodes (2)38(12) mm long; glume bodies (0.2)0.41.6 mm wide; lemmas 815 mm long, glabrous or uniformly hairy, awns (10)1540(50) mm long, moderately to strongly outcurving; blades 324 mm wide; culms (40)60180(220) cm tall, nodes usually concealed by the leaf sheaths.
43. Rachis internodes (2)35(7) mm long; spikelets 2(3) at most nodes, occasionally 1 or up to 5 at some nodes; paleas acute; blades (3)415(20) mm wide, usually firm and somewhat involute, dull green, drying grayish..................... 7. E. canadensis
43. Rachis internodes 512 mm long; spikelets 2 per node; paleas narrowly truncate; blades (8)1020(24) mm wide, flat, lax, dark green..................... 8. E. wiegandii
37. Glumes bases more or less terete, indurate, and without veins for 0.54 mm; glume bodies exceeding the adjacent lemmas by 15 mm or indistinguishable from the glume awns; lemma awns usually straight, occasionally contorted on the lower spikelets; rachis internodes (1.5)25(8) mm long.
44. Glumes persistent, glume bodies (0.2)0.30.8(1) mm wide, with 24 veins, the basal 0.52 mm straight or slightly curving; lemmas with hairs or scabrous; spikelets with 13(4) florets; spikes nodding, exserted from sheath.
45. Adaxial surfaces of the blades densely villous with fine whitish hairs, rarely just pilose on the veins, dark glossy green; spikes 412 cm long; internodes (1.5)23(4) mm long; spikelets with 12(3) florets; lemmas usually villous, sometimes glabrous, sometimes scabrous, 5.59 mm long, 0.51.5 mm longer than the paleas; anthesis usually in early June to early July...................................................................... 5. E. villosus
45. Adaxial surfaces of the blades glabrous or scabrous, dull green; spikes 725 cm long; internodes 35(8) mm long; spikelets with 23(4) florets; lemmas hispidulous or scabrous, 714 mm long, 15 mm longer than the paleas; anthesis usually in late June to late July....................................................................................... 6. E. riparius
44. Glumes disarticulating, glume bodies (0.5)0.72.3 mm wide, with (2)35(8) veins, the basal 14 mm clearly bowed out; lemmas often glabrous, sometimes scabrous; spikelets with 25(6) florets; spikes erect, exserted or sheathed.
46. Spikes (0.5)0.72.2(2.5) cm wide including the awns, exserted or sheathed; glume awns 010(15) mm long; spikelets appressed to slightly spreading; blades usually glabrous or scabridulous.
47. Lemma awns 515(20) mm long at midspike; blades of all leaves usually spreading or lax and flat, those of the lower leaves not markedly larger or more persistent than those of the upper leaves; anthesis in mid-June to mid-August, usually 12 weeks earlier than sympatric E. curvatus.................. 3. E. virginicus
47. Lemma awns 0.53(4) mm long at midspike; upper blades usually ascending and somewhat involute, blades of the lower leaves relatively short, narrow, and senescing earlier than those of the upper leaves; anthesis usually in late June to early August, 12 weeks later than sympatric E. virginicus............ 4. E. curvatus
46. Spikes (1.7)2.24.5(5.5) cm wide including the awns, exserted; glume awns (10)1530 mm long; spikelets spreading; blades glabrous or villous 48
48. Spikes with (6)916(20) nodes; internodes 47 mm long, about 0.3 mm thick at the thinnest portion; blades lax, dark glossy green under the glaucous bloom; auricles 23 mm long, often purplish black, at least in the central range of the species; anthesis usually in mid-May to mid-June E. macgregorii
48. Spikes with (10)1830(36) nodes; internodes 35 mm long, 0.30.8 mm thick at the thinnest portion; blades lax, or ascending and involute, usually dull green, with or without a glaucous bloom; auricles 02 mm long, usually purplish brown; anthesis usually in mid-June to late July E. glabriflorus
Elymus macgregorii R. Brooks & J.J.N. Campb.
Early Wildrye
Plants cespitose, not rhizomatous, usually glaucous. Culms 40120 cm, erect or slightly decumbent; nodes 48, mostly exposed, glabrous. Leaves evenly distributed; sheaths usually glabrous, rarely villous; auricles 23 mm, usually purplish black when fresh, sometimes light brown; ligules shorter than 1 mm; blades 715 mm wide, lax, dark glossy green under the glaucous bloom, adaxial surfaces usually glabrous, occasionally villous. Spikes 412 cm long, (1.7)2.23(4)4 cm wide, erect, exserted, with (6)916(20) nodes and 2 spikelets at all or most nodes, sometimes with 3 at some nodes; internodes 47 mm long, about 0.3 mm thick and 2-angled at the thinnest sections, usually glabrous or scabridulous beneath the spikelets. Spikelets 1015 mm, strongly divergent, glaucous, maturing to pale yellowish brown, with (2)34 florets, lowest florets functional; disarticulation below the glumes and each floret, the lowest floret often falling with the glumes. Glumes subequal, entire, the basal 13 mm terete or subterete, indurate, without evident venation, moderately bowed out, glume bodies 816 mm long, 11.8 mm wide, linear-lanceolate, widening or parallel-sided above the base, (2)45(8)-veined, usually glabrous, occasionally hirsute, sometimes scabrous, margins firm, awns (10)1520(25) mm, straight except the awns of yhe lowest spikelets occasionally contorted; lemmas 612 mm, usually glabrous, sometimes scabrous, occasionally villous, awns (15)2030 mm, straight; paleas 610 mm, apices obtuse; anthers 24 mm. Anthesis usually mid-May to mid-June. 2n = 28.
Elymus macgregorii grows in moist, deep, alluvial or residual, calcareous or other base-rich soils in woods and thickets, mostly east of the 100th
Elymus macregorii hybridizes with several species, but especially E. virginicus and E. hystrix (Campbell 2000). Western plants often have smaller, more condensed spikes, suggesting a transition to E. virginicus var. jejunus , but often with distinctly villous leaves. Transitions to E. virginicus var. jejunus can also be recognized to the north, where the dates of anthesis are delayed, but even in
2. Elymus glabriflorus (Vasey ex L.H. Dewey) Scribn. & C.R. Ball
Plants cespitose, not rhizomatous, often glaucous. Culms 60140 cm, erect; nodes 69, mostly concealed, glabrous. Leaves evenly distributed; sheaths glabrous or pubescent, often reddish brown; auricles absent or to 2 mm, usually purplish brown; ligules shorter than 1 mm; blades 715 mm wide, lax or somewhat involute and ascending, usually dull green, sometimes with a glaucous bloom, adaxial surfaces glabrous or densely short-villous. Spikes 620 cm long, (2)2.54(5.5) cm wide, erect, exserted, with (10)1830(36) nodes, usually with 2(3) spikelets per node, occasionally with up to 5 at some nodes; internodes 35 mm long, 0.30.8 mm thick and usually 4-angled at the thinnest sections, glabrous or pubescent beneath the spikelets. Spikelets 1020 mm, strongly divergent, often reddish brown at maturity, with (2)35(6) florets, lowest florets functional; disarticulation below the glumes and each floret, or the lowest floret often falling with the glumes. Glumes equal or subequal, entire, the basal 13 mm terete, indurate, moderately bowed out, without evident venation, glume bodies 718 mm long, (0.7)0.91.7 mm wide, linear-lanceolate, widening above the base, (3)45(7)-veined, smooth or scabrous, sometimes hirsute, margins firm, awns (10)1525(30) mm, straight except the awns of the lowest spikelets frequently contorted; lemmas 613 mm, smooth, scabrous, or hirsute, awns (15)2535(40) mm, straight except the awns of the lowest spikelets occasionally contorted; paleas 612 mm, obtuse; anthers 24 mm. Anthesis usually mid-June to late July. 2n = 28.
Elymus glabriflorus grows on moist, damp, or dry soil in open woods, thickets, and tall grasslands, sometimes spreading into old fields and roadsides. It is found in most of the southeastern
Elymus glabriflorus varies greatly in its pubescence, but without clear taxonomic relevance. Plants that combine pubescent spikelets and, usually, pubescent leaves with somewhat shorter spikes (612 cm versus 920 cm) and lemmas (610 mm versus 713 mm) are typical on relatively dry, infertile soils, especially in hilly interior regions, and are less frequent on the southeastern coastal plain. They have been named E. glabriflorus var. australis (Scribn. & C.R. Ball) J.J.N. Campb. In contrast, glabrous to scabrous plants that are often more robust usually grow on relatively moist or damp soils of bottomlands and upland depressions.
Elymus glabriflorus is most closely related to E. macgregorii and E. virginicus, forming occasional hybrids with both (Campbell 2000). It is sometimes confused with E. villosus , from which it differs in having erect spikes, and glumes that are bowed out and disarticulate at maturity. It has also been confused with E. canadensis , especially E. canadensis var. robustus , which may be derived from introgressants between the two species (Davies 1980). Hybrids with E. hystrix are also known, with apparent introgression at some range margins, but artificial crosses with other species failed in several cases (Church 1967a, 1967b).
Virginia Wildrye , Ιlyme de Virginie
Plants cespitose, not rhizomatous, sometimes glaucous, especially in the spikes. Culms 30130 cm, erect to slightly decumbent; nodes 49, concealed or exposed, usually glabrous, rarely pubescent. Leaves evenly distributed; sheaths usually glabrous, rarely hirsute, occasionally reddish or purplish; auricles absent or to 1.8 mm, pale brown; ligules shorter than 1 mm; blades 214(18) mm wide, usually spreading or lax, sometimes becoming involute, basal blades similar to the upper blades, adaxial surfaces usually smooth , sometimes scabridulous, usually glabrous, occasionally pubescent. Spikes (3)416(22) cm long, 12.2(2.5) cm wide, erect, the bases often sheathed, with 2 spikelets per node, rarely with 3 at some nodes; internodes 35 mm long, 0.250.5 thick at the thinnest sections, smooth and glabrous, or scabrous, or with hairs beneath the spikelets. Spikelets 1015 mm, appressed to slightly divergent, with (2)34(6) florets, lowest florets functional; disarticulation below the glumes and each floret, or the lowest floret often falling with the glumes. Glumes subequal or equal, the basal 14 mm terete, indurate, without evident venation, bowed out, yellowish, glume bodies 715 mm long, (0.5)0.72.3 mm wide, linear-lanceolate, widening above the base, 35(8)-veined, usually smooth or scabridulous, margins firm, awns 310(15) mm, straight; lemmas 610 mm, scabridulous, glabrous or villous-hirsute, awns (5)820(25) mm, straight; paleas 59 mm, obtuse; anthers 23.5(4) mm. Anthesis usually mid-June to late July (mid-August). 2n = 28.
Elymus virginicus is widespread in temperate North America, growing as far west as
1. Spikelets hispidulous to villous-hirsute, usually glaucous; anthesis usually in early July to mid-August var. intermedius
1. Spikelets usually glabrous or scabrous, glaucous or not; anthesis usually in mid-June to late July.
2. Spikes partly sheathed; glumes 12.3 mm wide, strongly indurate and bowed out in the basal 24 mm; plants not glaucous, becoming yellowish brown or occasionally somewhat purplish at maturity var. virginicus
2. Spikes exserted; glumes (0.5)0.71.5(1.8) mm wide, moderately indurate and bowed out in the basal 12 mm; plants usually glaucous, becoming yellowish or reddish brown at maturity.
3. Culms usually 70100 cm long, with 68 nodes; blades 315 mm wide, flat; spikes 420 cm long, not strongly glaucous; glumes indurate only in the basal 1 mm.. var. jejunusvar. jejunus
3. Culms usually 3080 cm long, with 46 nodes; blades 29 mm wide, often becoming involute; spikes 3.511 cm long, often strongly glaucous; glumes usually indurate in the basal 12 mm var. halophilusvar. halophilus
Elymus virginicus var. halophilus (E.P. Bicknell) Wiegand
Plants glaucous, often strongly so, becoming reddish brown at maturity. Culms usually 3080 cm; nodes usually 46, often exposed; ligules and auricles often pronounced. Blades 29 mm wide, often becoming involute and ascending, glabrous or slightly scabrous. Spikes 3.511 cm, exserted; spikelets usually glabrous to scabrous, strongly glaucous; glumes about 0.71.5 mm wide, usually somewhat indurate and bowed out in the basal 12 mm. Anthesis late June to late July.
Elymus virginicus var. halophilus grows in the moist to damp soil of dunes and brackish marsh edges along the northern Atlantic coast, from
Elymus virginicus var. intermedius (Vasey ex A. Gray) Bush
Plants often partly glaucous, becoming yellowish, reddish, or slightly purplish brown at maturity. Culms usually 60120 cm; nodes usually 48, concealed or exposed; auricles and ligules usually poorly developed. Blades 418 mm wide, lax or involute, glabrous, scabridulous, or occasionally pubescent. Spikes 622 cm long, sheathed or exserted; spikelets hispidulous to villous-hirsute, usually glaucous; glumes 0.81.2(2) mm wide, indurate and bowed out in the basal 24 mm. Anthesis early July to mid-August.
Elymus virginicus var. intermedius grows in moist, base-rich soil in open forests and thickets, especially on rocky, gravelly, or sandy banks of larger streams. It occurs from the central and southern Great Plains, through the central
Elymus virginicus var. jejunus (Ramaley) Bush
Plants usually glaucous, but not strongly so, becoming yellowish or reddish brown at maturity. Culms (50)70100(130) cm; nodes usually 68, often exposed; auricles and ligules often pronounced. Blades 315 mm wide, flat, usually scabridulous, rarely pubescent. Spikes 420 cm, exserted; spikelets usually glabrous to scabrous, sometimes glaucous; glumes (0.5)0.71.2(1.8) mm wide, indurate and bowed out only in the basal 1 mm. Anthesis mid-June to late July.
Elymus virginicus var. jejunus grows in moist to dry, sometimes alkaline or saline soil, in open, rocky, or alluvial woods, grasslands, glades, and disturbed places. It occupies the western range of the species, except for the Intermountain region. It is uncommon in the northeast, from
Elymus virginicus L. var. virginicus
Plants not glaucous, usually becoming yellowish brown, occasionally somewhat purplish at maturity. Culms (30)4090(130) cm; nodes usually 48, concealed or exposed; auricles and ligules sometimes pronounced. Blades 318 mm wide, lax or involute, usually scabridulous, rarely pubescent. Spikes 416(22) cm, partly sheathed; spikelets smooth or scabridulous, not glaucous; glumes 12(2.3) mm wide, indurate and bowed out in the basal 24 mm. Anthesis mid-June to late July.
Elymus virginicus var. virginicus grows in moist to damp or rather dry soil, mostly on bottomland or fertile uplands, in open woods, thickets, tall forbs, or weedy sites. It is widespread and abundant in the eastern range of the species, but also overlaps with var. jejunus in the Great Plains, east to
Awnless Wildrye
Plants cespitose, not rhizomatous, often glaucous. Culms 60110 cm, stiffly erect, or the base sometimes geniculate; nodes 69, concealed or exposed, glabrous. Leaves evenly distributed; sheaths glabrous, often reddish brown; auricles to 1 mm, sometimes absent; ligules shorter than 1 mm, ciliolate; blades 515 mm wide, the lower blades usually lax, shorter, narrower, and senescing earlier, the upper blades usually ascending and somewhat involute, adaxial surfaces smooth or scabridulous, occasionally scabrous. Spikes 915 cm long, (0.5)0.71.3 cm wide, erect, exserted or the bases slightly sheathed, with 2 spikelets per node; internodes 2.54.5 mm long, about 0.255 mm thick at the thinnest sections, smooth or scabrous beneath the spikelets. Spikelets 1015 mm, appressed, often reddish brown at maturity, with (2)34(5) florets, lowest florets functional; disarticulation below the glumes and beneath the florets, or the lowest floret falling with the glumes. Glumes equal or subequal, the basal 23 mm terete, indurate, strongly bowed out, without evident venation, glume bodies 715 mm long, 1.22.1 mm wide, linear-lanceolate, widening, 35-veined, usually glabrous or scabrous, occasionally hispidulous, rarely hirsute on the veins, margins firm, awns 03(5) mm; lemmas 610 mm, glabrous or scabrous, rarely hirsute, awns (0.5)13(4) mm, rarely 510 mm on the lemmas of the distal spikelets, straight; paleas 610 mm, obtuse, often emarginate; anthers 1.53 mm. Anthesis late June to mid August. 2n = 28, 42.
Elymus curvatus grows in moist or damp soils of open forests, thickets, grasslands, ditches, and disturbed ground, especially on bottomland. It is widespread from
Downy Wildrye
Plants cespitose, not rhizomatous, often persistently deep green. Culms 40130 cm, erect; nodes 48, concealed or exposed, glabrous. Leaves evenly distributed; sheaths villous-hirsute, pilose, or occasionally glabrate, occasionally reddish brown; auricles 13 mm, brownish; ligules less than 1 mm, entire or erose; blades 412 mm wide, lax, dark glossy green, adaxial surfaces densely velutinous-villous with fine whitish hairs, or rarely pilose only on the veins. Spikes 412 cm long, 1.53.5 cm wide, slightly or strongly nodding, exserted, with 2 spikelets per node, or rarely with 1 or 3 at a few nodes; internodes (1.5)23(4) mm long, 0.150.25 mm thick at the thinnest sections, usually hairy below the spikelets, rarely glabrous. Spikelets 712 mm, moderately divergent, with 12(3) florets, lowest florets functional; disarticulation above the glumes and beneath each floret. Glumes equal, 1225 mm including the often undifferentiated awns, the basal 0.52 mm terete, slightly indurate, straight or nearly so, without evident venation, glume bodies 710 mm long, (0.2)0.30.8 mm wide, linear-setiform, widening or parallel-sided above the base, 23(4)-veined, usually hirsute to hispid, occasionally scabrous to scabridulous, margins firm, awns 515 mm, straight; lemmas 5.59 mm, usually villous with fine, whitish, spreading hairs, especially near the margins and apices, sometimes glabrous or with coarser hairs, sometimes scabrous, awns 933 mm, straight; paleas 57.5 mm, obtuse, occasionally emarginate; anthers (1.6)23(4) mm. Anthesis early June to early July. 2n = 28.
Elymus villosus grows in moist to moderately dry, often rocky soils in woods and thickets, especially in calcareous or other base-rich soils, but it is also frequent on drier, sandy soils or damper, alluvial soils in glaciated regions. It extends from the Great Plains east to southern Quebec, northern New York, and Vermont south to Texas, Georgia, and
Elymus villosus is relatively uniform and distinct, although it has sometimes been confused with hairy plants of E. canadensis and E. glabriflorus . The hairs of E. villosus are fine, whitish, and consistently dense on the leaf blades, typically spreading in the spikelets; the hairs of the other species are typically stouter and more appressed in the spikelets. Plants called E. villosus var. arkansanas (Scribn. & C.R. Ball) J.J.N. Campb. are scabrous to glabrous in the spikes, except for the ciliate rachis margins, and often more robust. These are scattered over much of the species range, except in the north (from
Eastern Riverbank Wildrye , Ιlyme des Rivages
Plants cespitose, not rhizomatous, often somewhat glaucous. Culms 70160 cm, erect, sometimes rooting at the lower nodes; nodes 510, mostly concealed, glabrous. Leaves evenly distributed; sheaths usually glabrous or scabridulous, often reddish brown; auricles absent or to 2 mm, brown; ligules shorter than 1 mm; blades (5)815(25) mm wide, flat, lax, dull green, drying to grayish, adaxial surfaces glabrous or scabrous. Spikes 725 cm long, 24 cm wide, nodding, exserted, usually with 2 spikelets per node, rarely with 3 at some nodes; internodes 35(8) mm long, 0.20.35 thick at the thinnest sections, usually glabrous below the spikelets. Spikelets 1020 mm, strongly divergent, with 23(4) florets, lowest florets functional; disarticulation above the glumes and beneath each floret. Glumes equal or subequal, 1430 mm including the sometimes undifferentiated awn, the basal 0.52 mm terete, indurate, straight or nearly so, veins not evident, glume bodies 917 mm long, (0.3)0.50.8(1) mm wide, linear-setiform, entire, widening or parallel-sided above the base, 23(4)-veined, usually hispidulous or scabrous, rarely glabrous, margins firm, awns (5)818 mm, straight; lemmas 714 mm, usually hispidulous, sometimes scabrous, awns 1535 mm, usually straight, those of the basal spikelets occasionally contorted; paleas 69 mm, usually acute, sometimes obtuse to truncate, bidentate; anthers 22.7 mm. Anthesis late June to late July. 2n = 28.
Elymus riparius grows in moist, usually alluvial and often sandy soils in woods and thickets, usually along larger streams and occasionally along upland ditches. It is widespread in most of temperate east-central
Elymus riparius is relatively uniform and distinct. It is sometimes confused withE. canadensis , but that species has curving awns. It hybridizes occasionally with several other taxa, especially E. virginicus var. virginicus and E. hystrix , but the hybrids produce only late, depauperate spikes or none at all (e.g., Church 1958).
Great Plains Wildrye , Ιlyme du
Plants loosely cespitose, rarely with rhizomes to 4 cm long and 12 mm thick, often glaucous. Culms (40)60150(180) cm, erect or decumbent; nodes 410, mostly concealed by the leaf sheaths, glabrous. Leaves evenly distributed; sheaths smooth or scabridulous, glabrous or hirsute, often reddish brown; auricles 1.54 mm, brown or purplish black; ligules to 1(2) mm, truncate, ciliolate; blades (3)415(20) mm wide, usually firm, often ascending and somewhat involute, usually dull green, drying to grayish, adaxial surfaces usually smooth or scabridulous and glabrous, rarely sparsely hispid to villous. Spikes 630 cm long, 37 cm wide, usually nodding, sometimes pendent or almost erect, usually with 2(3) spikelets per node, occasionally to 5 at some nodes, rarely with 1 at some nodes but never throughout; internodes (2)35(7) mm long, or 510 mm long towards the base, 0.20.35 mm thick at the thinnest sections, glabrous or with a few hairs below the spikelets. Spikelets 1220 mm excluding the awns, more or less divergent, with (2)35(7) florets, lowest florets functional; disarticulation usually above the glumes and beneath each floret, rarely also below the glumes. Glumes usually equal, occasionally subequal, 1140 mm including the awns, the basal 01 mm subterete and slightly indurate, glume bodies 613 mm long, 0.51.6 mm wide, linear-lanceolate to subsetaceous, entire, widening or parallel-sided above the base, 35-veined, glabrous to scabrous-ciliate, rarely villous on the veins, margins firm, awns (5)1025(27) mm, straight to outcurving; lemmas 815 mm, glabrous, scabrous, hispid, or uniformly villous with the hairs generally appressed, awns (10)1540(50) mm, moderately to strongly outcurving, often contorted at the spike bases; paleas 713 mm, acute, usually bidentate; anthers 23.5 mm. Anthesis May to July. 2n = 28, rarely 42.
Elymus canadensis grows on dry to moist or damp, often sandy or gravelly soil on prairies, dunes, stream banks, ditches, roadsides, and disturbed ground, or, especially to the south, in thickets and open woods near streams. It is widespread in most of temperate North America, extending from the southwestern
Elymus canadensis is sometimes confused with E. riparius , from which it differs in having curved rather than straight awns; and with E. wiegandii , from which it differs in its less robust habit and narrower leaves. It can hybridize with Elymus glabriflorus , E. virginicus , E. hystrix and allies, E. glaucus , E. trachycaulus , Pseudoroegneria spicata , and other species. Subsequent introgression may have contributed to much of the diversity within the genus (Pohl 1959; Brown and Pratt 1960; Nelson and Tyrl 1978; Davies 1980; Campbell 2002). The three varieties recognized here show clear differences in their typical expression and evidence some geographic separation, but they may prove to be artificial reference points within a more or less continuous variation (Sanders et al. 1979). Nevertheless, crossing barriers sometimes exist between the varieties, and even between some sympatric strains (Church 1954, 1958, 1967a).
1. Lemmas usually villous or hispid; spikes nodding to almost pendent; internodes 47 mm long, often strongly glaucous var. canadensis
1. Lemmas usually smooth or scabridulous, occasionally hirsute; spikes usually nodding, occasionally almost erect; internodes 34 mm long, not strongly glaucous.
2. Glumes not clearly indurate or bowed out at the base, awns 1020 mm long; lemmas smooth or scabridulous, awns usually 2030 mm long, moderately outcurving; spikes 620 cm long var. brachystachys
2. Glumes often slightly indurate and bowed out at the base, awns 1525 mm long; lemmas occasionally hirsute, awns 3040 mm long, often strongly outcurving; spikes 1525(30) cm long var. robustus
Elymus canadensis var. brachystachys (Scribn. & C.R. Ball) Farw.
Spikes 620 cm, nodding, not strongly glaucous, often becoming yellowish or pale reddish brown, rarely with 3 spikelets per node; internodes mostly 34 mm. Glumes not clearly indurate or bowed out at the base, awns 1020 mm; lemmas smooth or scabridulous, awns usually 2030 mm, moderately outcurving.
Elymus canadensis var. brachystachys is widespread in the southern Great Plains from
Elymus canadensis L. var. canadensis
Spikes (6)1025(30) cm, nodding to almost pendent, often strongly glaucous, often with 3 spikelets per node; internodes 47 mm. Glumes not clearly indurate or bowed out at the base, awns 1025 mm; lemmas villous or hispid, awns 1540 mm, moderately to strongly outcurving.
Elymus canadensis var. canadensis is widespread across the northern range of the species, where anthesis is from late June to August, but it is also frequent as far south as
Elymus canadensis var. robustus (Scribn. & J.G. Sm.) Mack. & Bush
Spikes 1525(30) cm, moderately nodding, occasionally almost erect, not strongly glaucous, often becoming yellowish or pale reddish brown; internodes 34 mm. Glumes often slightly indurate and bowed out at the base, awns 1525 mm; lemmas smooth to scabridulous, or occasionally hirsute, awns 3040 mm, moderately or often strongly outcurving.
Elymus canadensis var. robustus occurs mostly in the east-central range of the species, from
Northern Riverbank Wildrye , Ιlyme de Wiegand
Plants cespitose, not rhizomatous, somewhat glaucous. Culms 100180(220) cm, erect; nodes 916, mostly concealed by the leaf sheaths, glabrous. Leaves evenly distributed; sheaths usually glabrous, occasionally villous, often reddish brown; auricles 13 mm, brown; ligules to 1 mm; blades (8)1020(24) mm wide, flat, lax, dark green, adaxial surfaces usually thinly pilose, with weak spreading hairs on the veins at least near the margins, sometimes villous or glabrous. Spikes 1030 cm long, 35 cm wide, pendent, the bases often barely exserted, with 2 spikelets per node; internodes 58(12) mm long, 0.20.3 mm thick at the thinnest sections, usually pubescent beneath the spikelets. Spikelets 1220 mm, divergent, with (3)46(7) florets, lowest florets functional; disarticulation above the glumes and beneath each floret. Glumes equal or subequal, 1230 mm including the often undifferentiated awns, the basal 0.51 mm subterete and slightly indurate, glume bodies 712 mm long, (0.2)0.40.9(1.1) mm wide, linear-setiform, entire, widening or parallel-sided above the base, 13(5)-veined, glabrous, hispidulous or villous, especially near the margins, margins firm, awns (5)815(18) mm, straight or flexuous; lemmas 1015 mm, usually uniformly appressed-villous, rarely scabrous-hirtellous or glabrous, awns 1525(30) mm, moderately to strongly outcurving; paleas 914 mm, narrowly truncate, minutely bidentate; anthers 23.5 mm. Anthesis from mid-July to early August. 2n = 28.
Elymus wiegandii grows in moist or damp, rich, alluvial soil, especially on sandy river terraces and in woods and thickets, primarily from
Elymus wiegandii is often confused with sympatric E. canadensis and E. diversiglumis , but it has a distinctive robust, broad-leaved habit. It is intermediate between the two in spike density and glume development. Occasional plants with glabrous leaves and less pendent spikes suggest introgression from E. canadensis, but artificial crosses produced no fertile F1 plants (Church 1958).
Plants cespitose, not rhizomatous, usually glaucous. Culms usually (40)60100(120) cm, erect or the bases somewhat decumbent; nodes 48, usually exposed, glabrous. Leaves evenly distributed; sheaths usually glabrous, occasionally hirsute; auricles 02 mm, pale or reddish brown; ligules to 1 mm; blades 39 mm wide, lax, pale green, adaxial surfaces densely short-pilose, hispidulous, or scabridulous, especially on the veins. Spikes 520 cm long, 25 cm wide, erect to slightly nodding, with 2 spikelets per node; internodes (5)814 mm long, 0.20.3 mm thick at the thinnest sections, without pronounced dorsal angles, often with green lateral bands, glabrous beneath the spikelets. Spikelets (6)915(22) mm, somewhat to strongly divergent, with 25 florets, lowest florets functional; disarticulation above the glumes and beneath each floret. Glumes subequal, 1530 mm including the weakly differentiated awns, the basal 01 mm subterete and indurate, glume bodies, when distinguishable, about 610 mm long, (0.2)0.30.5(0.7) mm wide, linear-setiform to setaceous, entire, widening or parallel-sided above the base, 13-veined, glabrous or scabridulous, margins firm, awns straight or flexuous; lemmas 710 mm, smooth or scabridulous, occasionally hirtellous especially near the margins, awns 1522 mm, straight to moderately outcurving; paleas 69 mm, obtuse or narrowly truncate, sometimes emarginate; anthers 24.5 mm. Anthesis May to July. 2n = 28.
Elymus interruptus grows in dry to moist, rocky soil, often in canyons, open woods, and thickets, in
Elymus interruptus is a poorly understood southern species that, at one extreme, used to be included in Elymus canadensis or, at the other extreme, used to include E. churchii, E. svensonii , and E. diversiglumis , three species that seem more closely allied to E. hystrix .
Common
Plants densely to loosely cespitose, sometimes weakly rhizomatous, often glaucous. Culms 30210 cm, erect or slightly decumbent; nodes 47, mostly exposed, usually glabrous, sometimes puberulent. Leaves evenly distributed; sheaths scabrous or smooth, glabrous or, particularly those of the lower leaves, retrorsely puberulent to hirsute, often purplish; auricles usually present, to 2.5 mm, often purplish; ligules to 1 mm, truncate, erose-ciliolate or entire; blades 213(17) mm wide, usually lax, sometimes slightly involute, adaxial surfaces glabrous, scabrous, or strigose on the veins, sometimes pilose to villous. Spikes 521 cm long, (0.2)0.52 cm wide, erect to slightly nodding, rarely somewhat pendent, usually with 2 spikelets per node, sometimes with 1 at all or most nodes, rarely with 3 at some nodes; internodes 48(12) mm long, 0.150.5 mm thick at the thinnest sections, angles scabrous, glabrous below the spikelets. Spikelets 825 mm, sometimes purplish at higher latitudes and elevations, appressed to slightly divergent, with (1)24(6) florets, lowest florets functional; disarticulation above the glumes and beneath each floret. Glumes subequal, 3/4 as long as or equaling the adjacent lemmas, bases often overlapping, usually flat and thin with evident venation, glume bodies (6)914(19) mm long, 0.61.5(2) mm wide, linear-lanceolate, entire, widening above the base, (1)35(7)-veined, 23 veins extending to the apices, glabrous, veins smooth or evenly scabrous, margins 0.10.2 mm wide, whitish hyaline, tapering towards the apices, unawned or awned, awns to 5(9) mm, straight; lemmas (8)914(16) mm, glabrous, scabrous, or short-hirsute, awns (0)130(35) mm, usually straight to flexuous, sometimes slightly curving; paleas 713 mm, keels straight or slightly concave, usually scabrous to ciliate, apices often bidentate; anthers 1.53.5 mm. Anthesis from May to July. 2n = 28.
Elymus glaucus grows in moist to dry soil in meadows, thickets, and open woods. It is widespread in western North America, from
Populations can differ greatly in morphology, especially in rhizome development, leaf width, pubescence, and the prevalence of solitary spikelets; their crossing relationships are partly correlated with such variation (Snyder 1950, 1951; Stebbins 1957, Wilson et al. 2001). Rhizome development and the production of solitary spikelets may also be environmental responses. Rhizomatous plants are more common on unstable slopes or sandy soils. Plants with solitary spikelets are more common on poor soil or in shade. They are often confused, particularly in the herbarium, with E. stebbinsii or E. trachycaulus . They differ from E. stebbinsii in their shorter anthers and awned glumes. Distinction from E. trachycaulus can be difficult with herbarium specimens, but is generally easy in the field, E. glaucus having more evenly leafy culms, laxer and wider blades, more tapered glumes that are almost always awned, and shorter anthers than the sympatric E. trachycaulus.
There are reports of natural hybrids with several other species of Elymus, including E. elymoides , E. multisetus (see E. Χhansenii , p. ??), E. trachycaulus, and E. stebbinsii. These hybrids often appear at least partially fertile. Elymus glaucus can also form intergeneric hybrids with Leymus and Hordeum (see ΧElyleymus , p. ??, and ΧLeydeum , p. ??).
The following three subspecies appear to be morphologically, ecologically, and geographically distinct. Plants found at elevations of up to 2200 m along the Pacific coast, with hairy leaf blades and lemma awns usually less than 20 mm long, have been called subsp. jepsonii (Burtt Davy) Gould , but Wilson et al. (2001) demonstrated that such plants are neither genetically nor ecologically distinct from those with glabrous leaf blades; they are included here in subsp. glaucus .
1. Lemma awns (0)15(7) mm long; glume awns 02 mm long... subsp. virescens
1. Lemma awns (5)1030(35) mm long; glume awns (0.5)19 mm long.
2. Blades 417 mm wide, adaxial surfaces glabrous or strigose, occasionally pilose to hirsute with hairs of fairly uniform length; glume awns (0.5)15(9) mm long............ subsp. glaucus
2. Blades 38 mm wide, densely short-pilose with scattered longer hairs; glume awns 38 mm long subsp. mackenzii
Elymus glaucus Buckley subsp. glaucus
Sheaths glabrous, scabrous or pubescent; blades usually 417 mm wide, adaxial surfaces glabrous or strigose, occasionally pilose to hirsute with hairs of fairly uniform length. Glume awns (0.5)15(9) mm; lemma awns (5)1025(35) mm.
Elymus glaucus subsp. glaucus grows throughout the range of the species, from sea level to 2500 m. It is absent from the area where E. glaucus subsp. mackenzii grows. It resembles E. hirsutus , differing in its erect spikes and in the pattern of its lemma pubescence. It also resembles the introduced E. dahuricus , from which it differs in its palea shape.
Elymus glaucus subsp. mackenzii (Bush) J.J.N. Campb.
Sheaths usually puberulent; blades 38 mm wide, densely short-pilose, with scattered longer hairs. Glume awns 38 mm; lemma awns 2030 mm.
Elymus glaucus subsp. mackenzii grows on limestone clifftops, rocky ledges, and glades, in open woods and thickets. It is known only from
Elymus glaucus subsp. virescens (Piper) Gould
Sheaths glabrous or scabrous; blades 210 mm wide, smooth or scabridulous to pubescent. Glume awns 02 mm; lemma awns (0)15(7) mm.
Elymus glaucus subsp. virescens generally grows in relatively dry or rocky soils along cliffs, bluffs, slopes, shores, and river banks, and in coniferous forests, chaparral, and other woodlands along the coast from
Plants cespitose, sometimes shortly rhizomatous. Culms 40140 cm, usually somewhat decumbent; nodes 47, mostly exposed, usually glabrous, occasionally puberulent. Leaves evenly distributed; sheaths usually glabrous and smooth, occasionally scabridulous or retrorsely hairy, sometimes purplish; auricles to 1.5 mm, often absent; ligules to 1 mm; blades 412 mm wide, lax, usually deep green, adaxial surfaces usually pilose or villous, occasionally puberulent or scabridulous. Spikes 620 cm long, 0.52 cm wide, nodding to pendent, with 2 spikelets per node, rarely with 3 at some nodes; internodes 310(12) mm long, 0.20.7 mm thick at the thinnest sections, usually glabrous, sometimes sparsely hairy. Spikelets 1220 mm, appressed to divergent, sometimes purplish at higher latitudes, with 24(7) florets, lowest florets functional; disarticulation above the glumes and beneath each floret. Glumes equal or subequal, the bases flat, occasionally indurate for 0.5 mm, veins usually evident, glume bodies (4.5)710(11) mm long, 0.71.5 mm wide, linear-lanceolate, entire, widening or parallel-sided above the base, 35-veined, usually scabridulous to scabrous, veins occasionally hirsute beyond midlength, margins hyaline or scarious, awns 110 mm, straight; lemmas 714 mm, smooth or scabridulous, lateral veins hairy, margins hairy beyond midlength, marginal hairs 0.51 mm, longer than those elsewhere, awns (2)830 mm, flexuous to moderately outcurving; paleas 613 mm, with hairs of varying lengths on the keels and apices, acute, bidentate; anthers 23.5 mm. Anthesis from May to July. 2n = 28.
Elymus hirsutus grows in moist to damp or dry soils in woods, thickets, and grasslands. Its range extends along the coastal mountains from the Aleutian Islands to northern Oregon, and inland to eastern
Elymus hirsutus is similar to E. glaucus , but its more pendent spikes, lemma pubescence pattern, and shorter glumes enable most specimens to be readily identified. Intermediates do exist; it is not known whether they reflect introgression or extremes of variation. It also forms occasional hybrids with Leymus mollis and Hordeum brachyantherum .
12. Elymus dahuricus Turcz. ex Griseb.
Plants cespitose, not rhizomatous, often glaucous. Culms 30130 cm, erect; nodes 47, mostly exposed, usually glabrous, occasionally short-hairy. Leaves evenly distributed; sheaths glabrous; auricles minute or absent; ligules 0.51 mm; blades 318 mm wide, lax, usually pale green, sometimes glaucous, adaxial surfaces usually smooth or scabrous on the veins, sometimes sparsely pilose. Spikes 723 cm long, 12.5 cm wide, usually slightly nodding, sometimes erect, usually with 2 spikelets per node, occasionally with 1 spikelet at some nodes; internodes 36 mm long, 0.20.8 mm thick at the thinnest sections, angles usually with scattered hairs. Spikelets 1015 mm, appressed to divergent, often purplish, with (2)34(5) florets, lowest florets functional; disarticulation above the glumes, beneath each floret. Glumes equal, the bases flat, not indurate, veins evident, glume bodies 69 mm long, 11.5 mm wide, linear-lanceolate, entire, widening or parallel-sided above the base, (1)35(7)-veined, veins scabrous, margins hyaline or scarious, awns (0)15 mm, straight or outcurving; lemmas (5)711 mm, usually glabrous and smooth throughout, sometimes scabrous to hispid distally and on the margins, marginal hairs not markedly longer than those elsewhere, awns (3)617(20) mm, usually somewhat outcurving from near the base; paleas 711 mm, keels spinose-ciliate, apices obtuse or truncate; anthers 1.53.5 mm. Anthesis from May to July. 2n = 42.
Elymus dahuricus is widespread in temperate central and eastern
Siberian Wildrye
Plants usually cespitose, sometimes weakly rhizomatous, usually glaucous, occasionally strongly so. Culms 40150 cm, erect or slightly geniculate at the base; nodes 69, usually exposed, glabrous. Leaves evenly distributed; sheaths glabrous or hirsute, often purplish; auricles to 1 mm, often absent; ligules to 1 mm; blades (3)514(16) mm wide, lax, adaxial surfaces usually pilose to hirsute on the veins, sometimes scabrous or smooth. Spikes 730 cm long, 25 cm wide, flexuous, nodding to pendent, with (1)2(34) spikelets per node, solitary spikelets usually basal or distal, rarely occurring throughout; internodes 510 mm long, 0.20.7 mm thick at the thinnest sections, mostly glabrous, sometimes scabrous below the spikelets, angles ciliate. Spikelets 1018 mm, appressed to divergent, usually becoming purplish, with (3)45(7) florets, lowest florets functional; disarticulation above the glumes, beneath each floret. Glumes equal or subequal, the bases flat, evidently veined, not indurate, glume bodies 38 mm long, 0.41(1.2) mm wide, linear-lanceolate to subsetaceous, entire, widening or parallel-sided above the base, 3(5)-veined, veins smooth or scabrous, margins hyaline or scarious, awns 16 mm, straight; lemmas 813 mm, densely scabridulous to scabrous, at least along the outer veins, awns 1025 mm, usually somewhat outcurving from near the base; paleas 812 mm, keels spinose-ciliate, bidentate, apices acute, 0.150.3 mm wide between the veins; anthers 0.91.7 mm. Anthesis from June to July. 2n = 28.
Elymus sibiricus grows in dry to damp grasslands and thickets, on slopes, eroding river banks, mud flats, coastal benches, dunes, clearings, and other disturbed areas, in southern Alaska, the southern Yukon Territory, the southwestern MacKenzie District in the Northwest Territories, and central British Columbia. Porsild and Cody (1980) suggested that at least some of the populations are native to
North American plants differ from Asian plants in several respects: they are up to 150 cm tall, versus 90 cm in
14. Elymus pringlei Scribn. & Merr.
Mexican Wildrye
Plants cespitose, not rhizomatous, usually somewhat glaucous. Culms 50110 cm, erect or somewhat geniculate at the base; nodes 69, mostly exposed, glabrous. Leaves evenly distributed; sheaths usually glabrous, occasionally pilose, hairs somewhat retrorse; auricles about 1 mm, pale or brownish; ligules about 1 mm, erose; blades 312 mm wide, lax, adaxial surfaces sparsely scabridulous, sometimes hispidulous to pilose on the veins, usually glaucous. Spikes 412 cm long, 23 cm wide, erect, the bases sometimes sheathed, with 2 spikelets per node; internodes 36 mm, about 0.2 mm thick at the thinnest sections, with 2 hispid dorsal angles, without green lateral bands. Spikelets 1015 mm excluding the awns, 1830 mm including the awns, appressed, with 35(6) florets, lowest florets functional; disarticulation above the glumes, beneath each floret. Glumes subequal, 1222 mm long including the undifferentiated awns, 0.20.3(0.6) mm wide, setaceous, entire, 01(2)-veined, tapering from the base, glabrous, margins firm, awns more or less straight; lemmas 810 mm, usually scabrous-hispid or thinly strigose, at least distally, awns 822 mm, straight or flexuous; paleas 78 mm, obtuse, often emarginate; anthers 2.54 mm. Anthesis May to June. 2n = unknown.
Elymus pringlei grows on moist slopes and canyons, in pine and deciduous tree woods, at 15002250 m in the Sierra Madre Orientale of eastern
15. Elymus texensis J.J.N. Campb.
Plants cespitose, not rhizomatous, glaucous. Culms 70110 cm, erect; nodes 46, mostly exposed, glabrous. Leaves evenly distributed; sheaths glabrous; auricles to about 2 mm, pale to purplish brown; ligules 12 mm, erose; blades 29 mm wide, lax or somewhat involute, adaxial surfaces thinly scabrous to hirsute or densely pilose. Spikes 920 cm long, 22.5 cm wide, erect to slightly nodding, with 2 spikelets per node; internodes (5)715(22) mm long, 0.10.3 mm thick at the thinnest sections, glabrous except for the ciliolate margins, with slight dorsal angles and green lateral bands along the concave sides. Spikelets 1320 mm excluding the awns, 2040 mm including the awns, appressed, with 46(8) florets, lowest florets functional; disarticulation above the glumes, beneath each floret. Glumes subequal, 1424 mm long including the undifferentiated awns, 0.10.3 mm wide, setaceous, entire, 01-veined, tapering from the base, glabrous, margins firm, awns more or less straight; lemmas 812 mm, smooth, glabrous, awns 825 mm, straight, flexuous or slightly curving; paleas about 711 mm, obtuse or truncate; anthers 4.56 mm. Anthesis in May. 2n = unknown.
Elymus texensis is known only from calcareous bluffs and hills in juniper woods and grassy areas on the
16. Elymus svensonii
Svensons Wildrye
Plants cespitose, not rhizomatous, strongly glaucous. Culms 50110 cm, erect; nodes 68, mostly exposed, often reddish brown, glabrous. Leaves evenly distributed; sheaths glabrous or villous, often somewhat purplish; auricles 12 mm, purplish or reddish brown; ligules to 1 mm, often reddish brown; blades 48(10) mm wide, lax, usually pale green, adaxial surfaces usually villous. Spikes 1016 cm long, 35 cm wide, nodding, with 2 spikelets per node; internodes (4)610(12) mm long, about 0.2 mm thick at the thinnest sections, flexuous, glabrous, without green lateral bands. Spikelets 1016 mm, usually appressed, with (3)45 florets, lowest florets functional; disarticulation above the glumes, beneath each floret. Glumes usually differing in length by more than 5 mm, sometimes vestigial to absent from the upper spikelets or throughout, (0)115(18) mm long including the undifferentiated awns, indurate at the base, 0.10.3 mm wide, setaceous to subulate, entire, 01-veined, tapering from the base, glabrous, margins firm, awns often curving outward; lemmas 810 mm, glabrous, veins occasionally hispidulous near the lemma apices, awns (8)1020(25) mm, moderately to strongly outcurving at maturity; paleas 79 mm, obtuse or truncate, occasionally emarginate; anthers 35 mm. Anthesis from mid-June to early July. 2n = unknown.
Elymus svensonii grows in dry, rocky soils in open woods of the interior low plateaus, mostly along bluffs of the Kentucky River and its tributaries in the bluegrass region of
Elymus svensonii, like E. diversiglumis and E. churchii , may be derived from hybrids between E. hystrix and E. canadensis (Church 1967a), even though E. canadensis currently has its eastern limit 50100 miles west of most E. svensonii. Elymus svensonii hybridizes naturally with E. hystrix, E. virginicus and other species of Elymus. Plants with little glume development are frequent; they appear to be introgressed by E. hystrix. Artificial crosses with E. interruptus have been successful, but those with E. diversiglumis have not (Church 1967a). Elymus svensonii resembles E. churchii; it differs in having less open spikes, shorter awns, more florets per spikelet, and more pubescent, glaucous foliage.
17. Elymus churchii J.J.N. Campb.
Churchs Wildrye
Plants cespitose, not rhizomatous, often somewhat glaucous. Culms 50120 cm, erect; nodes 48, exposed or concealed, often reddish brown or blackish, glabrous. Leaves evenly distributed; sheaths usually glabrous, sometimes pubescent at the summit; auricles 12 mm, often reddish brown or blackish; ligules to 1 mm, often reddish brown; blades 311 mm wide, lax, adaxial surfaces glabrous or short-pilose. Spikes 1018 cm long, 35 cm wide, slightly nodding, with 2 spikelets per node; internodes (5)713(18) mm long, about 0.2 mm thick at the thinnest sections, flexuous, with green lateral bands, glabrous except the dorsal angles hispid. Spikelets 1015 mm, usually appressed, with 3(5) florets, lowest florets functional; disarticulation above the glumes, beneath each floret. Glumes often differing in length by more than 5 mm, sometimes vestigial to absent from the upper spikelets or throughout, 015(20) mm long including the undifferentiated awns, indurate at the base, 0.10.3 mm wide, setaceous to subulate, entire, 01-veined, glabrous, margins firm, awns often outcurving; lemmas 810 mm, usually hairy, occasionally glabrous, awns (10)2030(35) mm, slightly to strongly outcurving at maturity; paleas 79 mm, obtuse to truncate, sometimes emarginate; anthers 2.53 mm, evident in June. 2n = unknown.
Elymus churchii grows in dry, rocky, often relatively base-rich soils, in open woods on ridges, and on bluffs and river banks. Its range includes the central Ouachita Mountains and the western Ozark Mountains in
Elymus churchii used to be included in Elymus interruptus (Steyermark 1963; Smith 1991). It is similar to the more eastern, disjunct Elymus svensonii , from which it differs in its more open spikes, longer awns, fewer florets per spikelet, and less pubescent, less glaucous foliage. Like E. svensonii, E. churchii may have originated from hybridization between E. canadensis and E. hystrix ; occasional intermediates with both species exist (Campbell 2002).
18. Elymus diversiglumis Scribn. & C.R. Ball
Unequal-Glumed Wildrye
Plants cespitose, not rhizomatous, sometimes moderately glaucous. Culms 70160 cm, erect; nodes 49, mostly exposed, glabrous. Leaves evenly distributed; sheaths glabrous, often purplish; auricles 12 mm, purplish or brownish black; ligules usually 12 mm; blades 517 mm wide, lax, adaxial surfaces usually pilose, at least on the veins, occasionally scabrous. Spikes 828 cm long, 35 cm wide, nodding to pendent, with 2 spikelets per node, rarely with 1 or 3 at a few nodes; internodes 46(9) mm long, 0.20.3 mm thick at the thinnest sections, margins and summits often pubescent. Spikelets 1016 mm, appressed, with 24(5) florets, lowest florets functional; disarticulation above the glumes, beneath each floret. Glumes usually differing in length by at least (3)4 mm, occasionally obsolete, (1)215(20) mm long including the undifferentiated awns, indurate at the base, (0.1)0.20.4(0.6) mm wide, setaceous, 01-veined, tapering from the base, scabrous or hispidulous at least towards the apices, margins firm, awns often outcurving; lemmas 712 mm, usually silvery-hirsute to sericeous, occasionally hirtellous or strigose, at least near the margins, backs sometimes scabrous, awns 1835 mm, moderately to strongly outcurving at maturity; paleas 710 mm, obtuse, occasionally emarginate; anthers 24 mm. Anthesis from early June to late July. 2n = 28.
Elymus diversiglumis grows in moist to dry, often base-rich and alluvial soils, in open woods, woodland margins, and thickets in the northern Great Plains, from
Elymus diversiglumis is a variable species that, like E. svensonii and E. churchii , may have originated from hybrids between Elymus canadensis var. canadensis and E. hystrix , although part of its range extends further west than the current distribution of the latter species. Elymus diversiglumis usually reaches anthesis 24 weeks earlier than sympatric populations of E. canadensis . Church (1954, 1958, 1967a) found that most artificial canadensishystrix hybrids, as well as some plants of E. diversiglumis itself, are sterile. Those that were not sterile could occasionally form fertile backcrosses with E. canadensis and, to a lesser extent, with E. hystrix. Introgressant populations involving all three species are known. Artificial crosses with other species have not been successful.
19. Elymus hystrix L.
Bottlebrush Grass , Glumeless Wildrye
Plants cespitose, not rhizomatous, occasionally glaucous, particularly the spikes. Culms 50140 cm, usually erect, occasionally geniculate below; nodes 48, exposed or concealed, glabrous. Leaves evenly distributed; sheaths usually glabrous, occasionally pilose, often purplish; auricles usually present, 0.53 mm, brown to black; ligules 12(3) mm; blades 416 mm wide, lax, usually deep glossy green, adaxial surfaces pilose or scabridulous. Spikes 720 cm long, 47 cm wide, more or less erect, usually with 2 spikelets per node, rarely with 3 at some nodes; internodes (3)48(10) mm long, (0.1)0.20.3(0.4) mm thick at the thinnest sections, flexuous, usually glabrous, sometimes scabrous or hirsute, usually with green lateral bands. Spikelets 1018 mm, strongly divergent to patent at maturity, with (1)24(6) florets, lowest florets functional; disarticulation above the glumes, beneath each floret. Glumes usually vestigial, sometimes 13 mm long, about 0.1 mm wide, subulate, entire, with no evident veins, occasionally to 10(20) mm long including the undifferentiated awns and differing in length by more than 5 mm, 0.10.2 mm wide, setaceous, tapering from the base, usually glabrous, occasionally appressed-puberulent to strigose, sometimes scabrous, usually straight, rarely somewhat curving, margins firm; lemmas 811 mm, usually glabrous, occasionally appressed-puberulent to strigose, especially near the margins and apices, awns (12)2040(47) mm, usually straight, rarely somewhat curving; paleas 711 mm, obtuse or truncate, occasionally emarginate; anthers 2.55 mm. Anthesis mid-June to early July. 2n = 28.
Elymus hystrix grows in dry to moist soils in open woods and thickets, especially on base-rich slopes and small stream terraces. It grows throughout most of temperate eastern North America, extending west to
Plants with pubescent lemmas have been recognized as Elymus hystrix var. bigelovianus (Fernald) Bowden . These occur infrequently north of a line from South Dakota through Kentucky to New Jersey, and are often mixed with the typical variety; pure populations are known in the northeastern United States. Plants with pubescent blades are also more prevalent to the north.
Elymus hystrix hybridizes with most eastern species of Elymus. Introgression may account for the considerable variation in glume development and spikelet appression among these species. Lack of glumes may be a recessive character, with even slight glume development indicating introgression (Church 1967b). Plants with relatively well-developed, subequal glumes are presumed to be of hybrid origin. Such plants include most material from the
20. Elymus multisetus (J.G. Sm.) Burtt Davy
Big Squirreltail
Plants cespitose, not rhizomatous. Culms 1565 cm, erect to ascending, usually puberulent; nodes 46, mostly concealed, glabrous. Leaves evenly distributed; sheaths glabrous or white-villous; auricles usually present, 0.51.5 mm; ligules to 1 mm, truncate, entire or lacerate; blades 1.54(5) mm wide, often ascending and involute, adaxial surfaces scabrous, pilose, or villous. Spikes 520 cm long, 515 cm wide, erect, sometimes partially enclosed at the base, with 2 spikelets per node, rarely with 34 at some nodes; internodes 35(8) mm long, 0.10.3 mm thick at the thinnest sections, glabrous beneath the spikelets. Spikelets 1015 mm, divergent, with 24 florets, lowest florets sterile and glumelike in 1 or both spikelets at each node; disarticulation initially at the rachis nodes, subsequently beneath each floret. Glumes subequal, (10)30100 mm including the awns, the bases indurate and glabrous, glume bodies about (2)510 mm long, 12 mm wide, setaceous, 23-veined, margins firm, awns (8)2590 mm, each split into 39 unequal divisions, scabrous, flexuous to outcurving from near the glume bases at maturity; fertile lemmas 810 mm, smooth or scabrous near the apices, 2 lateral veins extending into bristles to 10 mm, awns (10)20110 mm long, about 0.2 mm wide at the base, divergent to arcuate; paleas 79 mm, veins usually extending into about 1 mm bristles, apices acute to truncate; anthers 12 mm. Anthesis from late May to June. 2n = 28.
Elymus multisetus grows in dry, often rocky, open woods and thickets on slopes and plains, from central
21. Elymus elymoides (Raf.) Swezey
Plants cespitose, often glaucous, not rhizomatous. Culms 865(77) cm, erect or geniculate to slightly decumbent, sometimes puberulent; nodes 46, mostly concealed, usually glabrous, sometimes pubescent. Leaves evenly distributed; sheaths glabrous, scabrous, puberulent, or densely white-villous; auricles usually present, to about 1 mm, often purplish; ligules shorter than 1 mm, truncate, entire or lacerate; blades (1)24(6) mm wide, spreading or ascending, often involute, sometimes folded, abaxial surfaces glabrous to puberulent, adaxial surfaces scabrous, puberulent, hirsute, or white-villous. Spikes 320 cm long, 515 cm wide, erect to subflexuous, with 23 spikelets per node, rarely with 1 at some nodes; internodes 310(15) mm long, 0.10.4 mm thick at the thinnest sections, usually glabrous, sometimes puberulent beneath the spikelets. Spikelets 1020 mm, divergent, sometimes glaucous, at least 1 spikelet at a node with 24(5) florets, 14(5) florets fertile, sometimes all florets sterile in the lateral spikelets; disarticulation initially at the rachis nodes, subsequently beneath each floret. Glumes subequal, 20135 mm including the often undifferentiated awns, the bases indurate and glabrous, glume bodies 510 mm long, 13 mm wide, linear to setaceous, 13-veined, margins firm, awns 15125 mm, scabrous, sometimes split into 23 unequal divisions, flexuous to outcurving from near the base at maturity; fertile lemmas 612 mm, glabrous, scabrous, or appressed-pubescent, 2 lateral veins extending into bristles to 10 mm, awns 15120 mm long, about 0.4 mm wide at the base, often reddish or purplish, scabrous, flexuous to curved near the base; paleas 611 mm, veins often extending into bristles to 2(5) mm, apices acute to truncate; anthers 0.92.2 mm. Anthesis from late May to July. 2n = 28.
Elymus elymoides grows in dry, often rocky, open woods, thickets, grasslands, and disturbed areas, from sagebrush deserts to alpine tundra. It is widespread in western North America, from
Elymus elymoides intergrades with E. multisetus in parts of its southern range (
1. Rachis nodes with 3 spikelets, the central spikelet usually with 2 fertile florets, the florets of the lateral spikelets rudimentary to awnlike; lemma awns 1530 mm long..... subsp. hordeoides
1. Rachis nodes usually with 2 spikelets, each spikelet usually with (1)24(5) fertile florets; lemma awns 15120 mm long.
2. No spikelets appearing to have 3 glumes, the lowermost floret in each spikelet well developed; paleas rarely with the veins extended as bristles.............................. subsp. brevifolius
2. One or more of the spikelets at most nodes appearing to have 3 glumes, the lowest 12 florets sterile and glumelike; paleas usually with the veins extended as bristles.
3. Glumes with awns 1570 mm long, all glumes entire subsp. californicus
3. Glumes with awns 3585 mm long, one of the glumes at most nodes with the awn split into 2 or 3 divisions subsp. elymoides
Elymus elymoides subsp. brevifolius (J.G. Sm.) Barkworth
Longleaf Squirreltail
Culms 2565(77) cm, erect. Blades usually puberulent abaxially, sometimes glabrous. Spikes 720 cm, usually exserted, usually with 2 spikelets per node. Spikelets with (1)24(5) florets, lowermost floret functional. Glume awns 50125 mm, entire; lemma awns 50120 mm; paleas rarely with the veins extended as bristles.
Elymus elymoides subsp. brevifolius has a wide ecological and elevation range, extending from the arid
Elymus elymoides subsp. californicus (J.G. Sm.) Barkworth
Culms 840 cm, erect or decumbent. Blades usually glabrous abaxially, sometimes puberulent. Spikes 310 cm, often partly included, usually with 2 spikelets per node. Spikelets with (1)23 fertile florets, lowest 12 florets sterile and glumelike. Glume awns 1540(70) mm, entire; lemma awns 2570 mm, usually exceeding those of the glumes; paleas often with the veins extending as 12 mm bristles.
Elymus elymoides subsp. californicus grows in mid-montane to arctic-alpine habitats in western
Elymus elymoides (Raf.) Swezey subsp. elymoides
Common Squirreltail
Culms 1545 cm, erect to decumbent. Blades usually puberulent abaxially, sometimes glabrous. Spikes 415 cm, exserted or partly included, usually with 2 spikelets per node. Spikelets with (1)23(4) fertile florets, lowest 12 florets sterile and glumelike. Glume awns 3585 mm, often split into 2, sometimes 3, unequal divisions; lemma awns 2575 mm, usually exceeded by those of the glumes; paleas with the veins extending as bristles.
Elymus elymoides subsp. elymoides grows in desert and shrub-steppe areas of western North America, extending to the western edge of the
Elymus elymoides subsp. hordeoides (Suksd.) Barkworth
Culms 1020 cm, erect. Blades glabrous or puberulent abaxially. Spikes 36 cm, exserted or partly included, with 3 spikelets per node. Spikelets in the central position usually with 2 fertile florets, the lateral spikelets usually with rudimentary to awnlike florets. Glume awns 1550 mm, usually entire; lemma awns of the fertile florets 1530 mm; paleas with or without distinct bristles.
Elymus elymoides subsp. hordeoides grows in dry, rocky, often shallow soils, particularly in Artemisia rigidaPoa secunda communities, from eastern
22. Elymus trachycaulus (Link) Gould
Plants usually cespitose, sometimes weakly rhizomatous. Culms 30150 cm, ascending to erect; nodes usually glabrous. Leaves somewhat basally concentrated; sheaths usually glabrous, sometimes markedly retrorsely hirsute or villous; auricles absent or to 1 mm; ligules 0.20.8 mm, truncate; blades 25(8) mm wide, flat to involute, usually straight and ascending, abaxial surfaces usually smooth and glabrous, sometimes hairy, adaxial surfaces usually glabrous, sometimes conspicuously hairy. Spikes 425 cm long, 0.41 cm wide, erect, with 1 spikelet at all or most nodes; internodes (4)79(12) mm, edges scabrous, both surfaces smooth and glabrous. Spikelets 917(20) mm long, usually at least twice as long as the internodes, 36 mm wide, appressed, with 39 florets, lowest florets functional; rachillas glabrous or hairy, hairs to 0.3 mm; disarticulation above the glumes, beneath each floret. Glumes subequal, 517 mm long, from 3/4 as long as to longer than the adjacent lemmas, 1.82.3 mm wide, lanceolate to narrowly ovate, widest about midlength, usually green, purple at higher latitudes and elevations, flat or asymmetrically keeled for their full length, 37-veined, the keel vein usually scabrous, the others smooth or scabrous, only 1 vein extending to the apex, adaxial surfaces glabrous, margins hyaline or scarious, usually more or less equal, 0.20.5 mm wide, widest at or slightly beyond midlength, apices acute to awned, awns to 11 mm; lemmas 613 mm, glabrous, usually smooth proximally, often scabridulous distally over the veins, apices acute, usually awned, awns to 40 mm, usually straight, sometimes weakly curved if shorter than 10 mm; paleas subequal to the lemmas, keels straight or slightly outwardly curved below the apices, tapering to the apices, apices truncate, 0.150.3 mm wide, keel veins often extending beyond the intercostal region, sometimes forming teeth; anthers (0.8)1.22.5(3) mm. 2n = 28. Haplomes StH.
Elymus trachycaulus grows from sea level to 3300 m, usually in open or moderately open areas, but sometimes in forests. Its range extends from the boreal forests of North America east through
Jozwik (1966) recognized four groups within E. trachycaulus. Group I comprised unawned or shortly awned specimens; group II a polymorphic assemblage of awned specimens; group III a rather homomorphic group of specimens with secund spikes and relatively long awns; and group IV a relatively homomorphic group of unawned, high-elevation specimens. Jozwik concluded that group II consists of hybrids and backcrosses between E. trachycaulus and other species of Triticeae . He based this conclusion on consideration of field observations, artificial hybrids, the polymorphism of the specimens, and the geographic distribution of the group. This last was similar to that of unawned specimens of E. trachycaulus, but the populations were highly scattered within the area concerned. Jozwiks group III is treated here as Elymus trachycaulus subsp. subsecundus . His group IV is treated here as E. violaceus .
Elymus trachycaulus is often confused with E. stebbinsii . It differs in having shorter anthers, shorter internodes, and glumes that are sometimes awned. It may also be confused, particularly in the herbarium, with specimens of E. glaucus having solitary spikelets at all the spike nodes; it usually differs in having shorter anthers and less acuminate glumes. When, as is sometimes the case, the two species grow together, E. trachycaulus can be distinguished by its stiffer leaves. Elymus trachycaulus also resembles E. macrourus and E. alaskanus , but its glumes are longer relative to the lemmas. It also has less hairy rachillas than most plants of those species.
C.L. Hitchcock et al. (1969) treated Elymus trachycaulus as a subspecies of E. caninus ; it differs consistently from the latter species in glumes that are glabrous on the adaxial (inner) surface, in a chromosome interchange, and in its molecular characteristics (Sun et al. 1998). It also tends to have a more erect spike.
Elymus trachycaulus has been implicated in several interspecific and intergeneric hybrids. Named interspecific hybrids (and the other parent) are E. Χcayouetteorum (E. canadensis ), E. Χpalmerensis (E. sibiricus ), E. Χpseudorepens (E. lanceolatus ), and E. Χsaundersii (E. elymoides ). Hybrids withE. hystrix have been named ΧAgroelymus dorei Bowden ; the appropriate combination has not been made in Elymus. Named intergeneric hybrids are ΧElyhordeum macounii (Hordeum jubatum ), ΧElyleymus jamesensis (Leymus mollis ), and ΧElyleymus ontariensis (Leymus innovatus ). Hybrids with Elymus elymoides , E. multisetus , and Hordeum jubatum have brittle rachises and tend to be awned. Others are harder to recognize.
1. Lemma awns 1740 mm long, longer than the lemma body, straight; spikes somewhat 1-sided subsp. subsecundus
1. Lemmas unawned or with awns to 24 mm long, shorter or longer than the lemma body, straight or curved; spikes 2-sided.
2. Lemma awns 924 mm long putative hybrids between E. trachycaulus and other species of Triticeae
2. Lemmas unawned or with awns to 9 mm long, the awns sometimes curved.
3. Spike internodes 815 mm long; spikes 825 cm long; glumes unawned or with straight awns to 2 mm long; spikelet bases usually visible; lemmas unawned or with straight awns to 40 mm long subsp. trachycaulus
3. Spike internodes 45 mm long; spikes 510 cm long; glumes awned, awns 1.84 mm long; spikelet bases usually concealed; lemmas awned, awns 23 mm long, slightly curved subsp. virescens
Elymus trachycaulus subsp. subsecundus (Link) Α. Lφve & D. Lφve
Unilateral Wheatgrass
Culms 40110 cm. Spikes 725 cm, somewhat 1-sided. Spikelets with 37 florets, the bases usually visible. Glumes 1117 mm, long-acuminate or awned, awns to 11 mm; lemmas awned, awns 1740 mm, longer than the lemma body, straight.
Elymus trachycaulus subsp. subsecundus grows primarily in the
Elymus trachycaulus (Link) Gould subsp. trachycaulus
Slender Wheatgrass , Ιlyme ΰ Chaumes Rudes , Agropyre ΰ Chaumes Rudes
Culms 30150 cm. Spikes (4)830 cm long, 0.50.8 cm wide, 2-sided; internodes 815 mm. Spikelets with 39 florets, the bases usually visible. Glumes 517 mm, at least 1 vein scabrous to near the base, sometimes all veins scabrous, unawned or with straight awns shorter than 2 mm; lemmas unawned or awned, awns to 5 mm, straight.
Elymus trachycaulus subsp. trachycaulus grows throughout the habitat and range of the species, and exhibits considerably more variation than subsp. subsecundus . Two aspects of the variation that seem particularly worthy of further study are the glume venation, and the spacing of spikelets in the spikes. Plants with glumes having 57 well-developed, narrowly spaced veins are restricted to lower elevations and the southern portion of the subspecies range; northern plants and plants at higher elevations generally have 35 weakly developed and widely spaced veins. The former glumes resemble those of E. glaucus , with which E. trachycaulus subsp. trachycaulus is often sympatric; the latter, those of E. violaceus . Spikelet spacing also varies considerably. In at least some instances, plants with widely spaced spikelets appear to be associated with more shady habitats.
Elymus trachycaulus subsp. virescens (Lange) Α. Lφve & D. Lφve
Culms 2080 cm. Spikes 510 cm long, 0.50.8(1) cm wide, 2-sided; internodes 510 mm. Spikelets usually with the bases concealed. Glumes 9.513.5 mm, 1 vein scabrous over most of its length, the basal 1/4 usually smooth, the remaining veins scabrous or smooth, awned, awns 1.52 mm; lemmas awned, awns 2.510 mm, often curved.
Elymus trachycaulus subsp. virescens is restricted to
23. Elymus caninus (L.) L.
Bearded Elymus , Bearded Wheatgrass
Plants cespitose, not strongly rhizomatous. Culms 30130 cm, erect or geniculate, usually hairy on or below the nodes. Leaves evenly distributed; sheaths glabrous; auricles to 1.5 mm; ligules 0.21.5 mm; blades 1030 cm long, 410 mm wide, flat, both surfaces scabrous, adaxial surfaces sometimes with hairs over the veins, hairs to 0.5 mm, veins not prominent, widely spaced. Spikes 520 cm long, 0.51.5 cm wide including the awns, 58 mm wide excluding the awns, erect or arching, with 1 spikelet per node; internodes 4.57 mm, edges scabrous or ciliate, both surfaces hairy below the spikelets. Spikelets 1015(20) mm long, 25(7) mm wide, appressed to slightly divergent, with 26 florets; rachillas scabridulous or pubescent, often more densely pubescent distally; disarticulation above the glumes, beneath each floret. Glumes equal to unequal, 0.61 mm wide, lanceolate to narrowly ovate, usually green, flat or weakly keeled, keels eccentric, adaxial surfaces hairy, hairs often inconspicuous, hyaline margins sometimes widest distally, narrowing abruptly to the acute to acuminate apices; lower glumes 811 mm, 3-veined, usually awned, awns to 3 mm; upper glumes 1013 mm, 35-veined, sometimes awn-tipped, awns to 0.3 mm; lemmas 913 mm, glabrous, smooth to somewhat scabridulous distally, rounded on the back proximally, awned, awns 720 mm, straight or flexuous; paleas subequal to the lemmas, keels finely and densely ciliate over most of their length, straight or slightly outwardly curved, tapering to the apices, apices about 0.2 mm wide; anthers 23 mm. 2n = 28. Haplomes StH.
Elymus caninus is native to Eurasia; it is not known to be established in the Flora region. A.S. Hitchcock (1935, 1951) reported that it had been collected on ballast dumps in
The hairs on the inside of the glumes are difficult to see. Nevertheless, this is the single most reliable morphological character for distinguishing Elymus caninus from all other species of Elymus in this treatment. Elymus caninus is most likely to be confused with awned plants of E. trachycaulus. The two species also differ in their molecular characteristics, and in at least one chromosome interchange (Sun et al. 1998).
24. Elymus violaceus (Hornem.) Feilberg
High Elymus , Ιlyme Latiglume
Plants cespitose, not rhizomatous. Culms 1875 cm, often decumbent or geniculate; nodes usually glabrous. Sheaths glabrous; auricles about 0.5 mm; ligules 0.51 mm, truncate; blades 34 mm wide, flat, glabrous or hairy, abaxial surfaces less densely hairy and with shorter hairs than the adaxial surfaces, apices acute. Spikes 512 cm long, 0.40.7 cm wide excluding the awns, erect, with 1 spikelet per node; internodes 45.5 mm, edges ciliate. Spikelets 1119 mm, appressed, with (3)45 florets; rachillas hairy, hairs about 0.4 mm; disarticulation above the glumes, beneath each floret. Glumes 812 mm long, 1.22 mm wide, about 3/4 as long as to equaling the adjacent lemmas, narrowly ovate to obovate, often purplish, glabrous, sometimes scabrous, flat or equally keeled the full length, keels and other veins usually smooth, sometimes scabrous, 3(5)-veined, adaxial surfaces glabrous, margins usually unequal, the wider margin 0.31 mm wide, usually widest in the distal 1/3, apices acute to rounded, often awned, awns to 2 mm; lemmas glabrous or pubescent, hairs flexible, all similar, apices usually awned, awns 0.53 mm, straight; paleas subequal to the lemmas, tapering to the apices, apices about 0.4 mm wide; anthers 0.71.3 mm. 2n = 28. Haplomes StH.
Elymus violaceus grows in arctic, subalpine, and alpine habitats, on calcareous or dolomitic rocks, from
25. Elymus macrourus (Turcz. ex Steud.) Tzvelev
Hairy Elymus
Plants cespitose, sometimes appearing weakly rhizomatous. Culms 35100 cm, ascending to erect; nodes sometimes pubescent. Sheaths glabrous; auricles absent; ligules 0.51 mm, truncate to rounded; blades 310 mm wide, flat, usually glabrous, abaxial surfaces smooth or scabridulous, adaxial surfaces scabrous. Spikes 520 cm long, 0.40.8 cm wide, erect, with 1 spikelet per node; internodes 78 mm long, about 0.5 mm wide, glabrous below the spikelets. Spikelets 1220 mm, appressed, with 47 florets; rachillas hairy, hairs 0.30.5 mm; disarticulation above the glumes, beneath each floret. Glumes 610 mm long, 1/32/3 the length of the spikelets and to about 1/2 the length of the adjacent lemmas, 0.81.8 mm wide, widest at about midlength, lanceolate, flat, rounded, or symmetrically keeled, usually green or green tinged with purple, 34-veined, veins scabridulous, scabrous, or with hairs to 0.3 mm, usually glabrous elsewhere, margins subequal, about 0.3 mm wide, widest near midlength, apices acute, unawned or awned, awns to 1 mm; lemmas 812 mm, hairy throughout or glabrous distally, hairs all alike, 0.20.3 mm, apices unawned or awned, awns to 7 mm, straight; paleas subequal to the lemmas, tapering to the apices, apices about 0.8 mm wide; anthers 12 mm. 2n = 28.
Elymus macrourus grows on river banks and bars, lake shores, and hillsides in northwestern
Three varieties of Elymus macrourus are recognized in Russian treatments. It is not clear to which, if any, of the Russian species North American plants belong. A circumboreal study is needed, using plants grown from seeds collected in the wild. Seeds available as E. macrourus through germplasm resources appear to be misidentified.
Elymus macrourus is one of the parents in both Elymus Χpalmerensis and ΧElyhordeum pilosilemma .
26. Elymus alaskanus (Scribn. & Merr.) Α. Lφve
Plants cespitose or weakly rhizomatous. Culms 2090 cm, sometimes decumbent at the base, ascending to erect above; nodes usually pubescent, sometimes glabrous. Leaves sometimes basally concentrated; sheaths smooth or scabrous, glabrous or pilose; auricles absent or to 0.5 mm; ligules 0.21 mm, erose, ciliolate; blades 37 mm wide, flat, both surfaces smooth, scabrous, or pubescent. Spikes 3.514 cm long, 0.50.8 cm wide, erect or nodding distally, usually with 1 spikelet per node, occasionally with 2 at the lower nodes; internodes 310 mm long, 0.50.8 mm wide, mostly glabrous and smooth, edges scabrous or ciliate. Spikelets 915(20) mm, 25 times longer than the internodes, appressed, with 36 florets, rachillas hispidulous; disarticulation above the glumes, beneath each floret. Glumes 48 mm long, (1.2)1.52 mm wide, 1/32/3 as long as the as the adjacent lemmas, oblanceolate to obovate, flat, usually purplish, glabrous or hairy, hairs 0.30.5 mm, margins unequal, the widest margin 0.41 mm wide, both margins widest above the middle, apices unawned or awned, awns to 1 mm; lemmas 711 mm, glabrous or hairy, sometimes scabridulous, sometimes more densely hairy distally, hairs 0.20.6 mm, all alike, apices unawned or awned, awns to 7 mm, straight; paleas subequal to the lemmas, keels straight below the apices; anthers 12 mm. 2n = 28.
Elymus alaskanus extends across the high arctic of North America to extreme eastern
1. Glumes glabrous, scabrous or sparsely hairy, hairs to about 0.2 mm long; lemmas glabrous or with hairs to about 0.2 mm long........................................................................ subsp. alaskanus
1. Glumes and lemmas densely hairy, hairs 0.20.5 mm long subsp. hyperarcticus
Elymus alaskanus (Scribn. & Merr.) Α. Lφve subsp. alaskanus
Alaskan Elymus , Alaskan Wheatgrass
Plants cespitose or shortly rhizomatous. Culms 2590 cm, sometimes decumbent; nodes often exposed, glabrous or pubescent. Ligules 0.20.6 mm; blades 37 mm wide. Spikes 3.514 cm; internodes scabrous on the edges. Glumes glabrous, scabrous or sparsely hairy, hairs to about 0.2 mm; lemmas glabrous or hairy, sometimes more densely hairy distally, hairs about 0.2 mm, apices unawned or awned, awns to 7 mm, straight.
Elymus alaskanus subsp. alaskanus grows on river banks and hillsides, primarily north of 50° N latitude.
Elymus alaskanus subsp. hyperarcticus (Polunin) Α. Lφve & D. Lφve
High-Arctic Elymus
Plants cespitose, not rhizomatous. Culms 2035(50) cm, ascending to erect; nodes concealed. Ligules 0.51 mm, erose to ciliate; blades 2.55 mm wide. Spikes 4.57 cm; internodes 46 mm, ciliate, distal cilia longest. Glumes densely hairy, hairs 0.20.5 mm, apices mucronate or awned, awns to 1 mm; lemmas densely hairy, hairs 0.20.5 mm, apices awned, awns 15 mm, straight. 2n = 28.
Elymus alaskanus subsp. hyperarcticus grows on river banks and hillsides. It extends from the
27. Elymus lanceolatus (Scribn. & J.G. Sm.) Gould
Plants strongly rhizomatous, sometimes glaucous. Culms 22130 cm, erect; nodes glabrous. Leaves often mostly basal, sometimes more evenly distributed; sheaths glabrous or pubescent; auricles usually present on the lower leaves, 0.51.5 mm; ligules 0.10.5 mm, erose, sometimes ciliolate; blades 1.56 mm wide, generally involute, abaxial surfaces usually glabrous, adaxial surfaces strigose, ribs subequal in size and spacing. Spikes 3.526 cm long, 0.51 cm wide, erect to slightly nodding, usually with 1 spikelet per node, sometimes with 2 at a few nodes; internodes 3.515 mm long, 0.10.8 mm wide, glabrous or hairy. Spikelets 831 mm, 1.53 times longer than the internodes, appressed, with 311 florets; rachillas glabrous or hairy, hairs to 1 mm; disarticulation above the glumes, beneath each floret. Glumes subequal, 514 mm long, 1/23/4 the length of the adjacent lemmas, 0.71.3 mm wide, lanceolate, glabrous or hairy, smooth or scabrous, 35-veined, flat or weakly, often asymmetrically keeled, keels straight, margins narrow, tapering from the base or from beyond midlength, apices acute to acuminate, sometimes mucronate or shortly awned; lemmas 712 mm, glabrous or hairy, hairs all alike, sometimes scabrous, acute to awn-tipped, awns to 2 mm, straight; paleas about equal to the lemmas, keels straight below the apices, proximally smooth or scabrous, sometimes hairy, scabrous distally, intercostal region glabrous or with hairs, apices 0.20.3 mm wide; anthers (2.5)36 mm. 2n = 28.
Elymus lanceolatus grows in sand and clay soils and dry to mesic habitats. It is restricted to
Elymus lanceolatus is primarily outcrossing, and hybridizes with several species of Triticeae . Elymus albicans is thought to be derived from hybridization with the awned phase of Pseudoroegneria spicata . Judging from specimens of controlled hybrids, hybridization with E. trachycaulus and unawned plants of Pseudoroegneria spicata probably occur, but would be almost impossible to detect without careful observation in the field. Experimental hybrids are partially fertile, and capable of backcrossing to either parent (Dewey 1965, 1967, 1968, 1975, 1976).
1. Lemmas densely hairy, hairs flexible, some 1 mm long or longersubsp. psammophilus
1. Lemmas glabrous or with stiff hairs shorter than 1 mm.
2. Lemmas with hairs, not scabrous...... subsp. lanceolatus
2. Lemmas smooth, sometimes scabrous distally, mostly glabrous, sometimes the lemma margins proximally hairy subsp. riparius
Elymus lanceolatus (Scribn. & J.G. Sm.) Gould subsp. lanceolatus
Thickspike Wheatgrass
Culms 60130 cm. Spikes 1022 cm; internodes 715 mm, smooth, scabrous, or hairy distally. Spikelets 1028 mm. Lemmas not scabrous, moderately hairy, hairs stiff, shorter than 1 mm.
Elymus lanceolatus subsp. lanceolatus grows in clay, sand, loam, and rocky soils, and is widely distributed in the western Flora region. It is most likely to be confused with the octoploid Pascopyrum smithii ; it differs morphologically from that species in having more evenly distributed leaves and acute glumes that tend to taper from midlength or higher, rather than acuminate glumes that tend to taper from below midlength. In addition, the midvein of the glumes of E. lanceolatus is straight, whereas that of Pascopyrum smithii leans to the side distally.
Elymus lanceolatus subsp. psammophilus (J.M. Gillett & H. Senn) Α. Lφve
Sand-Dune Wheatgrass
Culms 2095 cm. Spikes 426 cm; internodes 3.513 mm, hairy at least distally. Spikelets 931 mm. Lemmas densely hairy, hairs flexible, usually many longer than 1 mm; paleas hairy between the keels, keels hairy proximally.
Elymus lanceolatus subsp. psammophilus tends to grow in sandy soils. It was originally described from around the
Elymus lanceolatus subsp. riparius (Scribn. & J.G. Sm.) Barkworth
Streambank Wheatgrass
Culms usually 2260 cm. Spikes 610 cm; internodes 3.510 mm, glabrous, sometimes scabrous. Spikelets 1017 mm. Lemmas smooth, sometimes scabrous distally, mostly glabrous, margins sometimes hairy proximally.
Elymus lanceolatus subsp. riparius grows throughout most of the western part of the range of E. lanceolatus, being more common in mesic habitats and clay soils than the other two subspecies.
28. Elymus stebbinsii Gould
Plants cespitose or shortly rhizomatous. Culms 60140 cm; nodes glabrous or retrorsely pubescent. Leaves evenly distributed; sheaths glabrous or pubescent; auricles usually present, 0.51.2 mm; ligules 0.33.5 mm, truncate to acute, sometimes long-ciliate; blades 46.5 mm wide, flat or the margins involute, straight. Spikes 1531 cm long, 0.41.5 cm wide including the awns, 0.40.8 cm wide excluding the awns, erect, with 1 spikelet per node; internodes 927 mm long, 11.3 mm wide, glabrous, smooth. Spikelets 1329 mm long, from shorter than to almost twice as long as the internodes, 2.55 mm wide, appressed, with 57 florets; rachillas glabrous; disarticulation above the glumes and beneath each floret. Glumes subequal, 7.512 mm long, 1.21.5 mm wide, rounded on the back, lanceolate, widest at about midlength, flat or rounded on the back, 5-veined, veins smooth, scabrous or just the midvein scabridulous, margins widest at about midlength, apices acute, unawned; lemmas 912 mm, glabrous, sometimes scabrous, acute, unawned or awned, awns to 28 mm, straight; paleas subequal to the lemmas, tapering, apices 0.20.3 mm wide; anthers (3.5)47 mm. 2n = 28.
Elymus stebbinsii is restricted to
1. Lemmas awned, awns 828 mm long; lower leaf sheaths rarely pubescent; spikelets 1322 mm long subsp. septentrionalis
1. Lemmas unawned or with awns to 8(12) mm long; lower leaf sheaths pubescent or glabrous; spikelets 1729 mm long......................................................................... subsp. stebbinsii
Elymus stebbinsii subsp. septentrionalis Barkworth
Northern Stebbins Wheatgrass
Lowest visible cauline node usually glabrous, rarely pubescent. Lower leaf sheaths usually glabrous, rarely pubescent. Spike internodes 921 mm. Spikelets 1322 mm. Lemmas awned, awns 828 mm.
Elymus stebbinsii subsp. septentrionalis grows primarily in the
Elymus stebbinsii Gould subsp. stebbinsii
Stebbins Wheatgrass
Lowest visible cauline node often pubescent. Lower leaf sheaths pubescent or glabrous. Spike internodes 16.327 mm. Spikelets 1729 mm. Lemmas unawned or awned, awns to 8(12) mm.
Elymus stebbinsii subsp. stebbinsii is best known from the coastal mountains south of
29. Elymus arizonicus (Scribn. & J.G. Sm.) Gould
Plants cespitose, not rhizomatous. Culms 45100 cm, erect or decumbent at the base; nodes glabrous or almost so. Leaves evenly distributed over the lower 1/2 of the culms; sheaths glabrous; auricles usually present, to 1 mm; ligules to 1 mm on the basal leaves, 13 mm on the flag leaves; blades 2.56 mm wide, lax, abaxial surfaces smooth and glabrous, adaxial surfaces scabrous, with scattered 0.51 mm hairs, veins close together. Spikes 1225 cm long, 2.56 cm wide including the awns, 1015 mm wide excluding the awns, flexuous, usually nodding or pendent at maturity, with 1 spikelet per node; internodes 1117 mm long, 0.41 mm wide, glabrous, mostly smooth, scabrous on the edges. Spikelets 1426 mm long, 68 mm wide, appressed to divergent, 1.52 times as long as the internodes, with 46 florets; rachillas glabrous; disarticulation above the glumes and beneath each floret. Glumes narrowly lanceolate, margins about 0.2 mm wide, 3(5)-veined, the bases flat, evidently veined, margins hyaline, widest at about midlength, acute or acuminate, unawned or awned, awns to 4 mm, straight; lower glumes 59 mm, upper glumes 810 mm; lemmas 815 mm, scabrous, rounded on the back, awns 1025 mm, arcuately diverging; paleas as long as or longer than the lemmas, tapering, apices truncate, about 0.3 mm wide; anthers 35 mm. 2n = 28.
Elymus arizonicus grows in moist, rocky soil in mountain canyons of the southwestern
30. Elymus bakeri (E. Nelson) Α. Lφve
Bakers Wheatgrass
Plants cespitose, not rhizomatous. Culms 3050 cm tall, 12 mm thick, ascending to erect; nodes glabrous. Leaves not basally concentrated; sheaths glabrous; auricles 0.30.6 mm; ligules 0.51 mm; blades 1220 cm long, 24 mm wide, stiff, abaxial surfaces smooth, glabrous, adaxial surfaces smooth or scabridulous, veins prominent, closely spaced. Spikes 812 cm long, 46 cm wide including the awns, about 1 cm wide excluding the awns, straight, erect or inclined, with 1 spikelet per node; internodes 59 mm long, about 0.8 mm wide, both surfaces glabrous, edges ciliate. Spikelets 1019 mm long, about twice as long as the adjacent internodes, 410 mm wide, appressed, with 45 florets; rachillas scabrous or hirtellous; disarticulation above the glumes, beneath each floret. Glumes 712 mm long, 1.42 mm wide, narrowly oblong, usually green or green tinged with purple, the bases evidently veined or indurate for less than 0.5 mm, 5-veined, veins scabrous, margins narrow, widest distally, apices acute, sometimes bifid, awned, awns 28 mm, straight or divergent; lemmas scabrous or smooth, apices often shortly bidentate, awns 1035 mm, arcuate to recurved; paleas equaling or slightly longer than the lemmas, tapering to the 0.20.4 mm wide apices; anthers 0.81.5 mm. 2n = 28.
Elymus bakeri grows in high, but not alpine, mountain meadows of
Reports of Elymus bakeri from
31. Elymus scribneri (Vasey) M.E. Jones
Scribners Wheatgrass
Plants cespitose, not rhizomatous. Culms 1535(55) cm, prostrate to strongly decumbent, at least at the base; nodes glabrous. Sheaths glabrous or shortly pilose; auricles usually present, 0.51 mm; ligules 0.20.4(0.7) mm, usually truncate, occasionally acute, entire to erose; blades 1.54 mm wide, usually involute, adaxial surfaces prominently ribbed. Spikes 3.510 cm long, 0.81.2 cm wide excluding the awns, 36 cm wide including the awns, usually with 1 spikelet per node, occasionally with 2 spikelets at the lower nodes; internodes 2.55(7) mm long, 0.51 mm wide, glabrous, mostly smooth, edges scabrous. Spikelets 915 mm long, 612 mm wide, appressed to ascending, with 36 florets; rachilla internodes 0.81.3 mm, scabridulous; disarticulation initially at the rachis nodes, subsequently beneath each floret. Glumes 49 mm long, 0.51 mm wide, mostly glabrous, midveins scabrous, 35-veined, entire, tapering into a divergent, 1230 mm awn; lemmas 710 mm, usually glabrous, occasionally scabridulous, awned, awns 1530 mm, divergent, scabridulous; paleas usually longer than the lemmas, apices ciliate, truncate or the veins extending into teeth, teeth about 0.5 mm; anthers 11.6 mm. 2n = 28.
Elymus scribneri grows in rocky areas in open subalpine and alpine regions, at 25003200 m, often in windswept locations, in southwestern
Several taxonomists have suggested that Elymus scribneri consists of fertile hybrids between E. violaceus and E. elymoides . This suggestion is supported by the frequency with which the three taxa are sympatric, the morphological variation exhibited by E. scribneri, and cytogenetic data (Dewey 1967).
32. Elymus sierrae Gould
Sierra Wheatgrass
Plants cespitose, not rhizomatous. Culms 2050 cm, prostrate or decumbent and geniculate; nodes 12, exposed, glabrous. Leaves basally concentrated; sheaths glabrous; auricles usually present, to 1 mm on the lower leaves; ligules 0.20.5 mm, erose; blades 15 mm wide, flat, abaxial surfaces smooth, glabrous, adaxial surfaces prominently ridged over the veins, with scattered hairs, hairs to 0.2 mm, veins closely spaced. Spikes 515 cm long, 1.52.5 cm wide including the awns, 0.71.2 cm wide excluding the awns, flexuous, erect to nodding distally, with 1 spikelet at most nodes, occasionally some of the lower nodes with 2 spikelets; internodes 515 mm long, 0.20.5 mm wide, both surfaces glabrous, edges ciliate, not scabrous. Spikelets 1520 mm, ascending to divergent, with 37 florets, rachillas glabrous; disarticulation above the glumes, beneath each floret. Glumes subequal, 69 mm long, 0.71 mm wide, lanceolate, glabrous, the bases evidently veined, apices entire, tapering into a 310 mm awn; lemmas 1216 mm, glabrous, sometimes scabridulous, apices bidentate, awned, awns 1530 mm, arcuately diverging to strongly recurved; paleas subequal to the lemmas, apices about 0.4 mm wide; anthers 23.5 mm. 2n = 28.
Elymus sierrae is best known from rocky slopes and ridge tops in the Sierra Nevadas, at 21303375 m, and is also found in
33. Elymus wawawaiensis J.R. Carlson & Barkworth
Snakeriver Wheatgrass
Plants cespitose, sometimes weakly rhizomatous. Culms (15)50130 cm, erect, mostly glabrous; nodes usually glabrous, sometimes slightly pubescent. Leaves more or less evenly distributed; basal sheaths glabrate, margins not evidently ciliate; auricles absent or to 1.2 mm; ligules 0.11.1 mm; blades to 28 cm long, 1.75 mm wide, involute when dry, adaxial surfaces usually densely pubescent, rarely sparsely pubescent. Spikes 520 cm long, 2.53 cm wide including the awns, erect to slightly nodding, with 1 spikelet per node; internodes 512 mm long, about 0.2 mm thick, about 0.3 mm wide, glabrous beneath the spikelets. Spikelets 1022 mm long, about twice as long as the internodes, 28.5 mm wide, appressed, with 410 florets; rachillas glabrous; disarticulation above the glumes, beneath each floret. Glumes 410 mm long, 0.51.3 mm wide, narrowly lanceolate, widest at or below midlength, glabrous, often glaucous, 13-veined, flat or weakly keeled, margins 0.10.2 mm wide, widest near midlength, apices usually acuminate, awned or unawned, awns to 6 mm; lemmas 612 mm, smooth or slightly scabrous, margins often sparsely pubescent proximally, awned, longest awns in the spikelets 928 mm, strongly divergent; paleas 7.210.5 mm, keels scabrous distally, tapering to the 0.20.3 mm wide apices; anthers 3.56 mm. 2n = 28.
Elymus wawawaiensis grows primarily in shallow, rocky soils of slopes in coulees and reaches of the Salmon, Snake, and Yakima rivers of Washington, northern
Elymus wawawaiensis resembles a vigorous version of Pseudoroegneria spicata, and was long confused with that species. It differs in its more imbricate spikelets and narrower, stiff glumes. In its primary range, E. wawawaiensis is often sympatric with P. spicata, but the two tend to grow in different habitats, E. wawawaiensis growing in shallow, rocky soils and P. spicata in medium- to fine-textured loess soil. The two species also differ cytologically, E. wawawaiensis being an allotetraploid, and P. spicata consisting of diploids and autotetraploids.
34. Elymus albicans (Scribn. & J.G. Sm.) Α. Lφve
Plants strongly rhizomatous. Culms 40100 cm, erect or decumbent only at the base, glabrous. Leaves somewhat basally concentrated; sheaths glabrous; auricles usually present, to 0.8 mm; ligules 0.20.5 mm, ciliolate; blades 13 mm wide, usually involute, adaxial surfaces scabrous to strigose. Spikes 414 cm long, 1.52.5 cm wide including the awns, 0.30.8 cm wide excluding the awns, erect, with 1 spikelet per node; internodes 614 mm long, 0.20.4 mm wide, glabrous or pubescent beneath the spikelets. Spikelets 1018 mm, 1.52 times longer than the internodes, appressed to ascending, with 37 florets; rachillas strigillose; disarticulation above the glumes, beneath each floret. Glumes subequal, 1/2 as long as to almost equaling the adjacent lemmas, glabrous or hairy, weakly keeled, keels and adjacent veins smooth to evenly and strongly scabrous from the base to the apices, margins 0.20.3 mm wide, apices acute, acuminate, or shortly awned; lower glumes 48 mm; upper glumes 4.58 mm; lemmas 7.59.5 mm, glabrous or densely hairy, awns 412 mm, at least some strongly divergent; paleas subequal to the lemmas, tapering to the 0.10.3 mm wide apices; anthers 35 mm. 2n = 28.
Elymus albicans grows primarily in the central Rocky Mountains and the western portion of the
Populations of E. albicans differ in their reproductive abilities (Dewey 1970). In some, most plants yield good seed; in others, most plants are sterile. Some of the fertile populations appear to be self-perpetuating; others appear to consist of recent hybrids and some backcrosses. Although treated here as a species, E. albicans could equally well be treated as a hybrid, Elymus Χalbicans. Plants with glabrous lemmas, presumed to be derived from crosses with glabrous individuals of E. lanceolatus, have sometimes been treated as a distinct taxon, e.g., Agropyron albicans var. griffithsii (Scribn. & J.G. Sm.) Beetle or A. griffithsii Scribn. & J.G. Sm. ; they are not formally recognized here.
35. Elymus repens (L.) Gould
Quackgrass , Couchgrass , Chiendent , Chiendent Rampant
Plants strongly rhizomatous, sometimes glaucous. Culms 50100 cm. Leaves sometimes somewhat basally concentrated; sheaths pilose or glabrous proximally; auricles 0.31 mm; ligules 0.251.5 mm; blades 610 mm wide, usually flat, abaxial surfaces glabrous or sparsely pilose, adaxial surfaces usually sparsely pilose over the veins, sometimes glabrous, veins smooth, widely spaced, primary veins prominent, separated by the secondary veins. Spikes 515 cm long, 0.51.5 cm wide, erect, usually with 1 spikelet per node, occasionally with 2 at a few nodes; internodes 46(9.5) mm long, 0.51.2 mm wide, smooth or scabrous, glabrous, evenly puberulent, or sparsely pilose, hairs to 0.3 mm. Spikelets 1027 mm, appressed to ascending, with 47 florets; disarticulation tardy, usually below the glumes, the spikelets falling intact. Glumes oblong, glabrous, keeled distally, keels inconspicuous and smooth proximally, scabrous and conspicuous distally, lateral veins inconspicuous, hyaline margins present in the distal 1/2, apices acute, unawned or awned, awns to 3 mm; lower glumes 8.811.4 mm, 36-veined; upper glumes 712 mm, 57-veined; lemmas 812 mm, glabrous, mostly smooth, sometimes scabridulous distally, unawned or with a 0.24(10) mm awn, awns straight; paleas 79.5 mm, keels ciliate from 1/2 to almost the entire length, apices emarginate, truncate, or rounded; anthers 47 mm. 2n = 22, 42. Genome StStH.
Elymus repens is native to Eurasia; it is now established through much of the Flora region, extending from
Godley (1947) demonstrated that lemma awn development, glaucousness, and the pubescence of the rachises are each effectively controlled by single genes. Long-awned plants are homozygous recessive, and awn-tipped plants homozygous dominant; glaucousness is dominant over non-glaucousness, and glabrous rachises over pubescent rachises. Awned plants appear to be established along the coasts of
Elymus repens is almost always a hexaploid. Most studies indicate that its genomic constitution is StStH, but Mason-Gamer (2001) demonstrated that it is genetically more complex than is implied by such a simple formula.
Green portion modified 11 Nov 2010 based on observation and discussion.
36. Elymus hoffmannii K.B. Jensen & Asay
Hoffmanns Elymus .
Plants slightly to moderately rhizomatous. Culms 54135 cm, glabrous. Leaves evenly distributed; sheaths glabrous; auricles absent or to 1 mm; ligules 0.61 mm, truncate, erose; blades 513 mm wide, flat to involute, abaxial surfaces smooth, glabrous, adaxial surfaces glabrous, veins closely spaced, all more or less equally prominent, smooth or scabrous. Spikes 1050 cm long, 0.81.8 cm wide, with 1 spikelet per node, glabrous below the spikelets; internodes 58 mm long, about 0.2 mm thick, about 0.3 mm wide, both surfaces hairy, hairs 0.20.4 mm. Spikelets 1527 mm, appressed to ascending, with 57 florets; rachillas scabridulous; disarticulation above the glumes, beneath the florets. Glumes equal, 511 mm long, 1.31.8 mm wide, stiff, lanceolate to linear-lanceolate, strongly rounded to keeled distally, keels inconspicuous and smooth on the proximal 1/31/2, conspicuous and with a few teeth distally, lateral veins inconspicuous, hyaline margins 0.10.2 mm wide, apices acuminate to awned, awns to 8 mm; lemmas 712 mm, glabrous, smooth, apices unawned or awned, awns to 12 mm, straight; paleas ciliate on the keels, apices about 0.6 mm wide; anthers 47 mm. 2n = 42. Genome StStH.
Elymus hoffmannii was described from a breeding line of plants developed from seeds collected in
The description of Elymus hoffmannii was explicitly written to encompass the cultivar NewHy. Nevertheless, the cultivar should be identified as ΧPseudelymus NewHy, because it is derived from an artificial cross between E. repens and Pseudoroegneria spicata . Because of its morphological similarity to plants obtained from the Turkish seed, Jensen and Asay suggested that E. hoffmannii had a similar parentage. NewHy was released as a cultivar in the 1980s. Its distribution within the Flora region is not known.
37. Elymus tsukushiensis Honda
Plants loosely cespitose, without conspicuous rhizomes. Culms 25100 cm tall, 1.33.5 mm thick, erect; nodes 46, glabrous. Leaves basal and cauline; sheaths glaucous, glabrous or with hairs, margins glabrous or ciliate distally; auricles 12 mm; ligules 0.20.7 mm, truncate; blades 310 mm wide, flattish, often glaucous. Spikes (6.5)1025 cm long, 1.44 cm wide including the awns, 0.720 cm wide excluding the awns, flexuous, nodding; rachises densely to sparsely hirsute on the edges, with about 0.2 mm hairs, glabrous elsewhere, glaucous; internodes (5)820 mm. Spikelets 1525 mm, loosely appressed or ascending, with 510 florets; rachillas hairy, hairs about 0.1 mm; disarticulation above the glumes, beneath the florets. Glumes lanceolate, tapering from about midlength, adaxial surfaces glabrous, hyaline margins about 0.1 mm wide, strongly keeled distally, midvein scabrous distally, other veins smooth or scabrous, apices acute to acuminate, sometimes awned, awns 25 mm; lower glumes 47 mm, 35-veined; upper glumes 58 mm, 5-veined; calluses glabrous; lemmas 812 mm, lanceolate, glabrous or pilose, apices acute, awned, awns 2040 mm, straight or flexuous; paleas from slightly shorter to longer than the lemmas, keels narrowly winged distally, not or scarcely extending beyond the intercostal region, distinctly outwardly curved below the apices, apices 0.30.5 mm wide; anthers 1.52.5 mm. 2n = 42. Genome StYH.
Elymus tsuskushiensis is native to northeastern
38. Elymus ciliaris (Trin.) Tzvelev
Plants loosely cespitose, without conspicuous rhizomes. Culms 30130 cm tall, 15 mm thick, erect or weakly decumbent; nodes 34, glabrous, glaucous. Leaves basal and cauline; sheaths glaucous, glabrous or with hairs, lower sheaths sometimes hairy, upper sheaths glabrous, margins sometimes ciliate; auricles 1.52.5 mm; ligules about 0.3 mm; blades 1025 cm long, 310 mm wide, glabrous or pilose. Spikes 1022 cm long, 1.52.5 cm wide including the awns, 0.81 cm wide excluding the awns, inclined to nodding, with 1 spikelet at all or most nodes; rachises scabrous on the edges, glabrous below the spikelets; internodes 1025 mm. Spikelets 522 mm long, about 5 mm wide, appressed, with 412 florets; disarticulation above the glumes, beneath the florets. Glumes narrowly elliptic to lance-oblong, apices acute to acuminate; lower glumes 511 mm; upper glumes 713 mm; lemmas 712 mm, mostly glabrous, glabrate, or sparsely hairy, margins with coarse stiff hairs, hairs to 1 mm, apices abruptly narrowed, awned, awns 1020 mm, scabrous, strongly outcurved to recurved; paleas 2/34/5 the length of the lemmas, keels winged distally, distinctly outwardly curved below the apices, apices 0.50.6 mm wide, truncate to rounded; anthers about 2 mm. 2n = 28. Genome StY.
Elymus ciliaris is native to northern
39. Elymus semicostatus (Nees ex Steud.) Melderis
Plants cespitose, not rhizomatous. Culms 45135 cm, erect or geniculately ascending, glabrous. Sheaths glabrous or villous; auricles to 1.5 mm; ligules 0.51.5 mm, truncate; blades 1530 cm long, 412 mm wide, sometimes villous, adaxial surfaces smooth or scabrous, primary and secondary veins alternating. Spikes 830 cm long, 12 cm wide including the awns, 0.51 cm wide excluding the awns, erect or nodding, usually with 1 spikelet per node, sometimes with 2 spikelets at the lower nodes; internodes 1020 mm long, about 0.8 mm wide, scabrous on the margins and on the surfaces, marginal prickles larger than those on the surfaces, hirtellous just below the spikelets. Spikelets 1630 mm, loosely appressed, with 68 florets; rachilla internodes about 0.8 mm, strigose, hairs to about 0.3 mm; disarticulation above the glumes, beneath each floret. Glumes subequal, 1018 mm long, 1.12 mm wide, elliptic-lanceolate, green, not keeled, 57-veined, veins more or less equally prominent, scabrous, apices acute to acuminate; lemmas 1014 mm, scabrous or puberulent dorsally, awned, awns (4)1218 mm, straight; paleas 3/4 as long as to slightly shorter than the lemmas, keels outwardly curved below the apices, apices 0.30.7 mm wide, truncate; anthers 36 mm. 2n = 28. Genome StY.
Elymus semicostatus is native to central Asia, from
Named hybrids
Elymus is notorious for its ability to hybridize. Most of its interspecific hybrids are partially fertile, permitting introgression between the parents. The descriptions provided below are restricted to the named interspecific hybrids. They should be treated with caution and some skepticism; some are based solely on the type specimen, because little other reliably identified material was available. Moreover, as the descriptions of the non-hybrid species indicate, many other interspecific hybrids exist.
The parentage of all hybrids is best determined in the field. Perennial hybrids, such as those in Elymus, can persist in an area after one or both parents have died out, but the simplest assumption is that both are present. Interspecific hybrids of Elymus that have disarticulating rachises presumably have E. elymoides or E. multisetus as one of their parents.
40. Elymus Χcayouetteorum (Boivin) Barkworth
Plants probably cespitose, not rhizomatous. Culms to 1 m tall, about 4 mm thick. Leaves not basally concentrated; sheaths smooth; ligules about 0.5 mm, glabrous; blades 2030 cm long, about 10 mm wide, both surfaces scabrous. Spikes about 25 cm, lower nodes with 1 spikelet, most middle to upper nodes with 2; internodes about 18 mm. Spikelets about 40 mm including the awns, about 20 mm excluding the awns, appressed, with 58 florets. Glumes 1215 mm, not or scarcely indurate, mostly smooth, veins scabrous, awns 35 mm; lemmas about 14 mm, glabrous, awns 1822 mm, not to moderately divergent; anthers 1.82 mm, indehiscent.
Elymus Χcayouetteorum consists of hybrids between Elymus trachycaulus and E. canadensis . The above description is based on the type specimen, which was collected on the Ilets-ΰ-Jιremie,
41. Elymus Χpalmerensis (Lepage) Barkworth & D.R. Dewey
Plants densely cespitose, shortly rhizomatous. Blades (2)48(15) mm wide, abaxial surfaces scabrous, adaxial surfaces pilose. Spikes 1430 cm long, 12.5 cm wide including the awns, 0.30.8(1.5) cm wide excluding the awns, drooping, with 12 spikelets per node; internodes 520 mm, scabrous on the angles. Spikelets with 39 florets. Glumes 410.5 mm long, 0.81.5 mm wide, oblong to lanceolate, scabrous, gradually or abruptly narrowing in the distal 1/31/4, 3(4)-veined, margins scarious, apices unawned or awned, awns to 15 mm; rachillas hairy; lemmas 8.515 mm, hairy, conspicuously keeled distally, awned, awns 310 mm; paleas 8.515 mm, retuse or truncate; anthers 12 mm.
Elymus Χpalmerensis is the name for hybrids between Elymus macrourus and E. sibiricus . It is known from disturbed sites around Palmer,
42. Elymus Χpseudorepens (Scribn. & J.G. Sm.) Barkworth & D.R. Dewey
False Quackgrass
Plants rhizomatous. Culms 30100 cm, ascending or erect, glabrous, mostly smooth, sometimes scabrous below the nodes. Leaves evenly distributed; sheaths glabrous; ligules to 0.5 mm; blades 1025 cm long, 27 mm wide, involute when dry, both surfaces scabrous, adaxial surfaces sparsely pilose, hairs 0.71 mm. Spikes 5.513 cm long, 0.40.6 cm wide, with 1 spikelet per node; internodes 3.55 mm. Glumes 818 mm, equaling or exceeded by the adjacent lemmas, more or less flat, 59-veined, margins unequal, the wider margins to about 0.3 mm, narrowly acute, sometimes awned, awns to 1 mm; lemmas 7.515 mm, smooth and glabrous proximally, scabrous distally, mucronate or awned, awns to 3 mm; anthers 1.52 mm.
Elymus Χpseudorepens consists of hybrids between E. lanceolatus and E. trachycaulus . It appears to be fairly common, having been reported from
43. Elymus Χyukonensis (Scribn. & Merr.) Α. Lφve
Plants rhizomatous. Culms about 60 cm, erect. Leaves somewhat basally concentrated; blades 3.56 mm wide. Spikes 610 cm long, 0.71.7 cm wide, with 1 spikelet per node; internodes 611 mm. Glumes 45.5 mm, about 1/2 the length of the adjacent lemmas, lanceolate, flat, hairy, apices acute or awn-tipped, awns shorter than 1 mm; rachillas densely hairy; lemmas 69 mm, densely villous, unawned; anthers 3.33.6 mm.
The parents of E. Χyukonensis have not been identified. Morphological and geographic considerations suggest that they may be E. lanceolatus subsp. psammophilus and E. alaskanus .
44. Elymus Χsaundersii Vasey
Plants cespitose, not rhizomatous. Culms 5080 cm, erect, glabrous or pilose. Leaves somewhat basally concentrated; sheaths retrorsely hairy; auricles to 1 mm; ligules 0.51 mm; blades 1015 cm long, 45 mm wide, flat, becoming involute when dry, tapering to the apices. Spikes 1025 cm long, 12.5 cm wide, with 1 spikelet per node; internodes 45 mm; disarticulation at the rachis nodes. Spikelets 1025 mm excluding the awns, with 36 florets. Glumes 68 mm, linear-lanceolate to lanceolate, 35-veined, veins scabrous, apices sometimes toothed, awned, awns 813 mm; lemmas 1013 mm, glabrous, smooth proximally, scabrous distally, awned, awns 2045 mm, outcurving; anthers 1.52 mm, usually indehiscent.
Elymus Χsaundersii comprises hybrids between E. trachycaulus and E. elymoides . Such hybrids are found throughout much of the western portion of the contiguous
45. Elymus Χhansenii Scribn.
Plants cespitose, not rhizomatous. Culms 60120 cm. Leaves evenly distributed; sheaths smooth; ligules to 1 mm; blades 1030 cm long, 28 mm wide, flat or the margins involute. Spikes 520 cm, straight or nodding, with 2+ spikelets per node; internodes about 10 mm; disarticulation in the rachises. Spikelets about 15 mm, with 35 florets. Glumes narrowly lanceolate, 23-veined, awned, awns 2535 mm; lemmas 1012 mm, awned, awns 4050 mm, outcurving; paleas subequal to the lemmas, truncate or bidentate.
Elymus Χhansenii refers to hybrids between E. glaucus and either E. elymoides or E. multisetus . It is not clear which of the latter two species is involved. It is a fairly common hybrid in those parts of western
46. Elymus Χpinalenoensis (Pyrah) Barkworth & D.R. Dewey
Plants cespitose, not rhizomatous. Culms 6090 cm tall, about 2 mm thick. Leaves somewhat basally concentrated; sheaths smooth or scabridulous; auricles to 1.5 mm; ligules 0.50.7 mm, rounded; blades 22.5 mm wide, those of the basal leaves 715 cm long, those of the flag leaves 27 cm long, abaxial surfaces smooth or scabridulous, glabrous or sparsely hairy basally, veins not evident, adaxial surfaces scabrous, sometimes with scattered hairs, veins prominently and equally ribbed. Spikes 814 cm long, about 5 cm wide including the awns, about 1 cm wide excluding the awns, nodding, lower nodes with 12 spikelets, upper nodes with 1 spikelet; internodes about 10 mm; disarticulation in the rachises and beneath each floret. Glumes 2231 mm including the awns, glume bodies 510 mm, midvein evident, scabrous, awns 1726 mm, divergent, scabrous; lemmas 1113 mm, smooth, awns 2040 mm, divergent, sometimes strongly divergent; anthers about 2 mm long, 11.5 mm thick.
Elymus Χpinalenoensis consists of hybrids between Elymus elymoides subsp. brevifolius and E. arizonicus (Pyrah 1983). It has been found in the Pinaleno and
47. Elymus Χebingeri G.C. Tucker
Plants cespitose, not rhizomatous. Culms 50135 cm, usually smooth, glabrous, sometimes retrorsely hairy; nodes glabrous or hairy. Leaves evenly distributed; sheaths smooth or scabridulous, hairy; ligules to 1 mm; blades 1426 cm long, to 12 mm wide, flat, both surfaces scabridulous, adaxial surfaces hairy. Spikes 817 cm, with (1)2+ spikelets per node; internodes 48 mm. Spikelets diverging at about 45° from the rachises, not patent. Glumes usually subequal, 1520 mm, bases indurate, bodies lanceolate to subulate, scabrous, sometimes the lower glumes reduced to a stub; lemmas 810 mm, glabrous or strigose, sometimes scabrous, awns 2329 mm, straight, scabrous; anthers 22.9 mm. Caryopses seldom formed.
Elymus Χebingeri is the name for hybrids between E. virginicus and E. hystrix . It is frequently found, often with later hybrid generations and introgressants to the two parents, where the two parental species grow together. It has been reported from southern