14.26 DESCHAMPSIA P. Beauv.
Mary E. Barkworth

Plants usually perennial, sometimes annual; cespitose or tufted. Culms 5–140 cm, hollow, erect. Leaves usually mainly basal, often forming a dense tuft; sheaths open; auricles absent; ligules membranous, decurrent, rounded to acuminate; blades often all or almost all tightly rolled or folded and some flat, sometimes most flat, others rolled or folded. Inflorescences terminal panicles, open or contracted; disarticulation above the glumes, beneath the florets. Spikelets 3–9 mm, with 2(3) florets in all or almost all spikelets, florets usually bisexual, sometimes viviparous; rachillas hairy, usually prolonged more than 0.5 mm beyond the base of the distal floret, sometimes terminating in a highly reduced floret. Glumes subequal to unequal, usually exceeding the adjacent florets, often exceeding all florets, 1- or 3-veined, acute to acuminate; calluses antrorsely strigose; lemmas obscurely (3)5–7-veined, rounded over the back, apices truncate-erose to 2–4-toothed, awned, awns usually attached on the lower 1/2 of the lemmas, occasionally subapical, straight to strongly geniculate, slightly to strongly twisted proximally, straight distally; paleas shorter than the lemmas, 2-keeled, keels often scabrous; lodicules 2, lanceolate to ovate-lanceolate, usually entire; anthers 3; ovaries glabrous; styles 2. Caryopses oblong; embryos about 1/4 the length of the caryopses. x = 7. Named for Louise Auguste Deschamps (1765–1842), a French naturalist.

Deschampsia includes 20–40 species. It is best represented in the Americas and Eurasia, but it grows in cool, damp habitats throughout the world. Seven species are native to the Flora region; none of the remaining species have been introduced.

Deschampsia differs from Vahlodea, which it used to include, in having primarily basal, rather than primarily cauline, leaves, and hairy rachillas that extend more than 0.5 mm beyond the base of the distal floret in a spikelet. Trisetum differs from Deschampsia primarily in its more acute, bifid lemmas, and in having awns that are inserted at or above the midpoint of the lemmas. In Deschampsia, the awns are usually inserted near the base.

Because the treatments of Deschampsia brevifolia and D. sukatschewii were revised shortly before going to press, the maps are preliminary, particularly with respect to the Canadian distribution of these two species.

Lemma length, awn attachment, and awn length should be examined on the lower florets within the spikelets. The upper florets often have shorter lemmas, and shorter awns that are attached higher on the back than those of the lower florets.

SELECTED REFERENCES Aiken, S.G., L.L. Consaul, and M.J. Dallwitz. 1995 on. Grasses of the Canadian Arctic Archipelago: Descriptions, illustrations, identification and information retrieval. http://www.mun.ca/biology/delta/arcticf/poa/index.htm; Chiapella, J. 2000. The Deschampsia cespitosa complex in central and northern Europe: A morphological analysis. Bot. J. Linn. Soc. 134:495–512; Chiapella, J. and N.S. Probatova. 2003. The Deschampsia cespitosa complex (Poaceae: Aveneae) with special reference to Russia. Bot. J. Linn. Soc. 142:213–228; Clarke, G.C.S. 1980. Deschampsia Beauv. Pp. 225–227 in T.G. Tutin, V.H. Heywood, N.A. Burges, D.M. Moore, D.H. Valentine, S.M. Walters, and D.A. Webb (eds.). Flora Europaea, vol. 5. Cambridge University Press, Cambridge, England. 452 pp.; Hultén, E. 1960. Flora of the Aleutian Islands and Westernmost Alaska Peninsula with Notes on the Flora of Commander Islands. J. Cramer, Weinheim, Germany. 376 pp.; Kawano, S. 1966. Biosystematic studies of the Deschampsia caespitosa complex with special reference to the karyology of Icelandic populations. Bot. Mag. (Tokyo) 79:293–307; Lawrence, W.E. 1945. Some ecotypic relations of Deschampsia caespitosa. Amer. J. Bot. 32:298–314; McLachlan, K.I., S.G. Aiken, L.P. Lefkovitch, and S.A. Edlund. 1989. Grasses of the Queen Elizabeth Islands. Canad. J. Bot. 67:2088–2105; Tsvelev, N.N. 1995. Deschampsia. Pp. 150–163 in J.G. Packer (ed., English edition). Flora of the Russian Arctic, vol. 1, trans. G.C.D. Griffiths. University of Alberta Press, Edmonton, Alberta, Canada [English translation of A.I. Tolmachev (ed.). 1964. Arkticheskaya Flora SSSR, vol. 2. Nauka, Leningrad [St. Petersburg], Russia].

[Click here for interactive version of dichotomous key, here for multientry interactive key].

1. All or most spikelets viviparous; panicle branches smooth D. alpina
1. All or most spikelets bisexual or, if viviparous, the panicle branches scabrous (2)
2. Plants annual; awns strongly geniculate D. danthonioides
2. Plants perennial; awns straight to strongly geniculate (3)
3. Lemmas scabridulous or puberulent, dull D. flexuosa
3. Lemmas glabrous, shiny (4)
4. Glumes mostly green, apices purple; panicles narrowly elongate, 0.5–1.5(2) cm
wide, appearing greenish D. elongata
4. Glumes purplish proximally, sometimes over more than 1/2 their surface, whitish to golden distally; panicles usually pyramidal or ovate, sometimes narrowly elongate, 0.5–30 cm wide, appearing bronze to dark purple (D. cespitosa complex) (5)
5. Spikelets 6–7.5 mm long; culms sometimes decumbent and rooting at the lower nodes; plants of sandy areas around lakes in the Northwest Territories and
northern Saskatchewan D. mackenzieana
5. Spikelets 2–7.6 mm; culms erect, not rooting at the lower nodes; plants of gravels, wet meadows, and bogs, widely distributed in cooler regions of North America (6)
6. Spikelets strongly imbricate, often rather densely clustered on the ends of the branches, sometimes evenly distributed on the branches; glumes and lemmas dark purple proximally for over more than 1/2 their surface; lemmas 2.2–4 mm long D. brevifolia
6. Spikelets usually not or only moderately imbricate, not in dense clusters at the ends of the branches; glumes usually purple over less than 1/2 their surface, often with a green base, a distal purple band, and pale apices; lemmas 2–5(7)mm long (7)
7. Basal blades with 5–11 ribs, usually most or all ribs scabridulous or scabrous, outer ribs often more strongly so, sometimes the ribs only papillose or puberulent, usually at least some blades flat and 1–4 mm wide, the majority folded or rolled and 0.5–1 mm in diameter; lower glumes often scabridulous distally over the midvein; lower panicle branches often
scabridulous or scabrous, sometimes smooth D. cespitosa
7. Basal blades with 3–5 ribs, ribs usually smooth or papillose, sometimes puberulent or the outer ribs scabridulous, all blades of the current year usually strongly involute and hairlike, 0.3–0.5(0.8) in diameter; lower glumes smooth over the midvein; lower panicle branches usually smooth,
sometimes sparsely scabridulous; D. sukatschewii

1. Deschampsia cespitosa (L.) P. Beauv.

Plants perennial; loosely to tightly cespitose. Culms (7) 35–150 cm, erect, not rooting at the lower nodes. Leaves mostly basal, sometimes forming a dense 10–35 cm tuft; sheaths glabrous; ligules 2–13 mm, scarious, decurrent, obtuse to acute; blades 5–30 cm long, usually at least some flat and 1–4 mm wide, the remainder folded or rolled and 0.5–1 mm in diameter, adaxial surfaces with 5–11 prominent ribs, ribs usually all papillose, scabridulous, or scabrous, sometimes puberulent, outer ribs sometimes more strongly so than the inner ribs. Panicles 8–30(40) cm, 4–30 cm wide, usually open and pyramidal, sometimes contracted and ovate; branches straight to slightly flexuous, usually strongly divergent, sometimes strongly ascending, lower branches often scabridulous or scabrous, particularly distally, with not or only moderately imbricate spikelets. Spikelets 2.5–7.6 mm, ovate to V-shaped, laterally compressed, usually bisexual, sometimes viviparous, bisexual spikelets usually with 2(3) florets, rarely with 1. Glumes lanceolate, acute; lower glumes 2.7–7 mm, entire, 1–3-veined, midvein sometimes scabridulous, at least distally; upper glumes 2–7.5 mm, 1–3-veined, lanceolate, midvein smooth or wholly or partly scabridulous; callus hairs 0.2–2.3 mm; lemmas 2–5(7) mm, smooth, shiny, glabrous, usually purple over less than 1/2 their surface, purple or green proximally, if green, often with a purple band about midlength, usually green or pale distally, usually awned, awns (0.5)1–8 mm, attached from near the base to about midlength, straight or geniculate, sometimes exceeding the glumes; anthers 1.5–3 mm. Caryopses 0.5–1 mm. 2n = 18, 24, 25, 26–28, about 39, 52. The voucher specimens for these counts have not been examined.

Deschampsia cespitosa is circumboreal in the Northern Hemisphere, and also grows in New Zealand and Australia. It is an attractive taxon that grows in wet meadows and bogs, and along streams and lakes, from sea level to over 3000 m in cool-temperate, but not arctic, habitats.

There are widely varying opinions concerning the taxonomic treatment of Deschampsia cespitosa. Tsvelev, Aiken, Murray, and Elven (per Murray, pers. com. 2005) recommend a narrow circumscription, and consider D. cespitosa to be introduced and mostly ruderal in regions other than Europe and western Siberia. Chiapella and Probatova (2003) adopted a much broader interpretation of D. cespitosa, treating many of the species recognized in, for example, Tsvelev (1995) as subspecies. There have been no interdisplinary, global studies of the complex. The circumscription adopted here is narrower than has been customary in North America. Some of the distribution records shown, particularly those from the northern part of the region, may reflect the broad interpretation of the species.

The name Deschampsia cespitosa is based on Aira cespitosa L. Linnaeus chose not to spell the epithet of the basionym “caespitosa”. Consequently, the correct spelling of the epithet when combined with Deschampsia is “cespitosa”.

Lawrence (1945) demonstrated that, in western North America, Deschampsia cespitosa exhibits both ecotypic differentiation and a high degree of plasticity. The following three subspecies intergrade.

1. Panicles contracted at anthesis, the branches appressed to ascending; glumes 4.5–5.8 mm long, midvein of the lower glumes scabrous
distally subsp. holciformis
1. Panicles open at anthesis, the branches strongly divergent to drooping; glumes 2–7.5 mm long; midvein of the lower glumes smooth or scabridulous distally (2)
2. Plants often glaucous; glumes 4.4–7.5 mm long; awns usually exceeding the lemmas; plants of the northwest coast of North
America subsp. beringensis
2. Plants not glaucous; glumes 2–6 mm long; awns exceeded by or exceeding the lemmas; plants widespread in North America subsp. cespitosa

Deschampsia cespitosa subsp. beringensis (Hultén) W.E. Lawr.
Beringian Hairgrass

Plants loosely cespitose, often glaucous. Culms (15)70–140 cm. Ligules 4.5–13 mm; blades 5–12 cm long, 2–4 mm wide. Panicles 9–40 cm long, 8–30 cm wide, open, pyramidal; branches divergent, scab-ridulous to scabrous. Spikelets 4.5–8 mm, greenish, not to somewhat imbricate. Glumes from exceeding to exceeded by the distal floret, lengths usually 5+ times widths; lower glumes 4.3–7 mm, midveins smooth or scabridulous distally; upper glumes 4.4–7.5 mm; callus hairs 0.7–1.6 mm; lemmas 3–5(7) mm, apices 4-toothed or bifid, usually mostly green, awns 3.3–6.3 mm, straight to weakly geniculate, attached within the proximal 1/3 of the lemma; anthers (1.5)1.9–2.5 mm. 2n = 26.

Deschampsia cespitosa subsp. beringensis is primarily a coastal species, growing up to 800 m along the Aleutian chain and the southern coast of Alaska south to Sonoma County, California, and west to the Kamchatka Peninsula, Russia. Typical plants are tall, glaucous, have long ligules and spikelets, and long, narrow glumes, but in the Pribiloff Islands and at scattered locations elsewhere, they intergrade with plants that are only 15–25 cm tall and also have smaller spikelet parts (Lawrence 1945). Deschampsia cespitosa subsp. beringensis differs from D. mackenzieana primarily in its coastal distribution and lower chromosome number. It supposedly differs from D. cespitosa subsp. cespitosa in having long glumes but, as the descriptions indicate, there is considerable overlap in this and other characters. The morphological, geo-graphic, and ecological boundaries between the two subspecies need further study.

Deschampsia cespitosa (L.) P. Beauv. subsp. cespitosa
Tufted Hairgrass, Deschampsie Cespiteuse

Plants densely cespitose, not glaucous. Culms (7)35–150 cm. Ligules 2–8 mm; blades 5–25 cm long, 1.5–3.5 mm wide when flat. Panicles 8–30 cm long, 4–30 cm wide, open, nodding, pyramidal; branches, both primary and secondary, usually divergent, usually sparsely to moderately scabridulous or scabrous, sometimes smooth. Spikelets 2.5–7 mm, not to slightly imbricate. Glumes subequal to the distal floret, lengths often less than 5 times widths; lower glumes 2.5–5 mm, midveins smooth or scabridulous distally; upper glumes 2–6 mm; lemmas 2–4 mm, purple and/or green proximally, green to gold distally, the purple portion usually less than 1/2 the surface area, awns 1–8 mm, usually attached near the base, sometimes attached near midlength, straight or geniculate, exceeded by or exceeding the distal floret; anthers 1.5–2 mm.

Deschampsia cespitosa subsp. cespitosa is treated here as a circumboreal taxon that is most prevalent in boreal and temperate North America, growing at 0–3000 m; many reports from arctic and alpine North America refer to what are treated here as D. sukatschewii or D. brevifolia. Even with this narrower interpretation, D. cespitosa is highly polymorphic. Plants with long awns are more prevalent in western North America but, within that region, do not appear to show any geographic or ecological preference (Lawrence 1945). Larger plants are difficult to distinguish from D. cespitosa subsp. beringensis. The morphological, geographic, and ecological boundaries between D. cespitosa subsp. cespitosa and subsp. beringensis need further study.

Many cultivars of Deschampsia cespitosa subsp. cespitosa have been developed. At one time, the most frequently cultivated plants were distinguished by their combination of large (20–40 cm) panicles and small (2.5–4 mm) spikelets, and were called D. cespitosa var. parviflora (Thuill.) Coss. & Germ. or D. cespitosa subsp. parviflora (Thuill.) K. Richt. Such plants are treated here as one part of the spectrum of variation in subsp. cespitosa.

The name Deschampsia cespitosa var. glauca (Hartm.) Lindm. has been applied in eastern North America to glaucous plants less than 75 cm tall, with spikelets only 3–4.5 mm long. Unfortunately, the name is illegitimate; there is no legitimate name available for such plants.

Deschampsia cespitosa subsp. holciformis (J. Presl) W.E. Lawr.

Plants cespitose, sometimes glaucous. Culms 50–125 cm. Ligules 3–4.3 mm; blades 15–30 cm long, 1–4 mm wide when flat. Panicles 10–25 cm long, 3–8 cm wide, dense; primary and secondary branches appressed to ascending, scabridulous to densely scabrous. Spikelets 5.5–8 mm, usually strongly imbricate. Glumes usually exceeded by the distal floret, often purplish over more than 1/2 their area; lower glumes 4.6–5.8 mm, midveins scabrous distally; upper glumes 4.5–5.6 mm; callus hairs 1–2.3 mm; lemmas 3.8–4.5 mm, often purplish over more than 1/2 their area, awns 2–3 mm, straight to slightly geniculate, attached near or slightly above the middle of the lemma; anthers 2.5–3 mm. 2n = 26.

Deschampsia cespitosa subsp. holciformis grows in coastal marshes and sandy soils, from the Queen Charlotte Islands, British Columbia, to central California. It intergrades and is interfertile with D. cespitosa subsp. beringensis, differing in its closed panicles, scabrous veins on the lower glumes, and more strongly imbricate spikelets. There are relatively few collections; it is not clear whether this reflects lack of collecting or rarity.

2. Deschampsia mackenzieana Raup
Mackenzie Hairgrass

Plants loosely cespitose. Culms 30–80 cm, smooth, glabrous, sometimes decumbent at the base and rooting at the lower nodes. Basal leaves not forming a tuft; sheaths smooth; ligules 4–7.5 mm, acute; blades 1–3 mm wide, convolute to involute, abaxial surfaces smooth, adaxial surfaces scabrous. Panicles 10–20 cm long, 8–14 cm wide; branches ascending to laxly diverging or reflexed, somewhat scabrous, longest branches at the lower nodes usually undivided for 1/3–1/2 their length. Spikelets 6–7.5 mm, bisexual. Glumes acuminate, equaling or slightly longer than the distal floret; callus hairs 1.5–2 mm; lemmas 4.5–5.5 mm, awns attached on the lower 1/4–2/3, inconspicuous, weakly geniculate, from shorter than to exceeding the lemma by approximately 2 mm; anthers 1.5–2.7 mm. 2n = 52.

Deschampsia mackenzieana grows on the sandy shores and dunes around Great Slave Lake, Northwest Territories, and Lake Athabasca, Saskatchewan. The decumbent culms of some plants may be a response to shifting substrate.

3. Deschampsia sukatschewii (Popl.) Roshev.
Deschampsie Naine

Plants perennial; usually densely cespitose. Culms 5–70 cm, erect or strongly geniculate at the first node, glabrous. Leaves mostly basal, sometimes forming a dense, moss-like tuft 5–20 cm in diameter; sheaths smooth, glabrous; ligules 1.5–8 mm, acute; blades 0.5–8 cm long, usually strongly rolled and 0.5–1.3 mm in diameter, rarely flat and to 1.5(2) mm wide, abaxial surfaces smooth, adaxial surfaces with 3–5(6) ribs, ribs smooth, the outer ribs sometimes scabrous. Panicles 3.5–17 cm long, 1.5–9 cm wide, usually open and pyramidal, sometimes closed and ovate; branches 0.5–6 cm, spreading to reflexed, flexuous, smooth. Spikelets 3.5–5.2 mm, shiny, purplish, with 2(3) florets. Glumes lanceolate, sometimes purplish over the proximal 1/2, acute to acuminate; lower glumes 2.7–4.8 mm, 0.8–0.9 times the length of the spikelets, 1–3-veined, veins smooth; upper glumes 3–5 mm, equaling or exceeding the lowest floret, 1–5-veined; callus hairs 0.3–1 mm; lemmas 2–4 mm, smooth, shiny, glabrous, sometimes purplish distally, apices rounded or truncate, erose, awns 0.8–2.5 mm, arising at or below midlength, straight, slender, only slightly or not exserted; anthers 0.7–2.5 mm. 2n = 26, 28, 36, ca. 39.

Deschampsia sukatschewii is a circumboreal species that extends from northern Russia through Alaska, northern Canada, and Greenland to Svalbard, and southward in the Rocky Mountains to Nevada and Utah. It ranges from short plants that form dense, mossy tufts on the Arctic coast to larger plants in subalpine and alpine habitats of the Rocky Mountains that have frequently been included in D. cespitosa.

Arctic taxonomists recognize two subspecies of Deschampsia sukatschewii in arctic North America: the amphiberingian subsp. orientalis (Hultén) Tzvelev that extends to the northern coast of Alaska and the western Northwest Territories; and subsp. borealis (Trautv.) Tzvelev, which is circumpolar in the arctic. Chiapella and Probatova (2003) treated these two subspecies, and subsp. sukatschewii, as subspecies of D. cespitosa. Efforts to circumscribe infraspecific taxa of D. sukatschewii for this treatment failed.

4. Deschampsia brevifolia R. Br.

Plants perennial; cespitose, not glaucous. Culms 5–55 cm, erect, glabrous. Leaves often forming a basal tuft; sheaths glabrous; ligules 1–4.5 mm, acute or acuminate, entire; blades 2–12 (16) cm long, usually 0.3–0.8 mm in diameter, folded or con-volute, 0.5–2 mm wide when flat, abaxial surfaces glabrous, adaxial surfaces glabrous or sparsely hirtellous, sometimes scabrous, blades of flag leaves 0.8–3 cm. Panicles 1.5–10(12) cm long, 0.5–2(11) cm wide, usually dense, oblong-ovate to narrowly cylindrical; branches 1–3.6(6) cm, straight, usually stiff, erect to ascending, usually smooth or almost so, scabrules separated by 0.2+ mm, spikelet-bearing to near the base. Spikelets 2.3–6 mm, ovate to obovate, with 2(3) florets. Glumes subequal to equal, 2.5–5.6 mm, purplish over more than 1/2 their surface, lanceolate, smooth, acuminate or acute; lower glumes 1-veined, smooth; upper glumes exceeding to exceeded by the lowest floret, 3-veined; callus hairs 0.2–2 mm; lemmas 2.2–4 mm, oblong or lanceolate, smooth, shiny, glabrous, awns (0.2)0.7–4 mm, usually equaling or exceeding the lemmas, straight or weakly geniculate, usually attached from near the base to midlength, occasionally connate almost their full length; anthers 1.2–2.5 mm. 2n = 26, 27, 28, about 50, 52.

Deschampsia brevifolia is a circumboreal taxon that grows in wet places in the tundra, often in disturbed soils associated with riverbanks, frost-heaving, etc. It is interpreted here as extending southward through the Rocky Mountains to Colorado, where it grows at elevations up to 4300 m. It is to be expected from high elevations in British Columbia and Alberta; specimens currently identified as D. cespitosa, in which D. brevifolia is often included as a subspecies, need to be examined.

In its typical appearance, Deschampsia brevifolia is quite distinctive because of its dark, narrow panicles. Culm height can vary substantially from year to year, probably in response to the environment. Aiken et al. (1995 on) reported that plants transplanted from Eureka Sound, Ellesmere Island (80° 9' N 86° 0' W) to Iqaluit, Baffin Island (64° 44' N 68° 28' W) became smaller and more stunted; most of those transplanted to Ottawa, Ontario (45° 18' N 75° 50' W) died, but some grew larger than at the original site, and developed more diffuse panicles.

5. Deschampsia alpina (L.) Roem. & Schult.
Alpine Hairgrass, Deschampsie Alpine

Plants perennial; densely cespitose. Culms 8–45(65) cm, smooth, glabrous. Leaves form-ing a basal tuft; sheaths smooth, glabrous; ligules 1.5–7.5 mm, glabrous, acute to acuminate, entire; blades 2–8 cm long, 0.5–2 mm wide, usually folded or flat, sometimes some loosely involute, both surfaces glabrous, smooth. Panicles (4)8–16 cm; branches 2–8 cm long (excluding the blades of bulbous florets), straight, ascending, smooth. Spikelets usually viviparous, their length varying with age, rarely bisexual and 4–6.3 mm. Glumes subequal, exceeding the lowest floret in sexual spikelets, keels smooth, apices acuminate; callus hairs about 0.8 mm; lemmas 5–7 mm, smooth, shiny, glabrous, unawned or awned, awns to 4 mm, straight, attached from below midlength to near the apices; paleas vestigial or absent. 2n = 52, 56.

Deschampsia alpina grows in damp, rocky places, on calcareous substrates with low organic content, in Greenland and northeastern Canada and, outside the Flora region, in the mountains of Scandinavia and Russia in the Kola Peninsula and Novaya Zemlya. Plants of D. alpina differ from viviparous plants of D. cespitosa in having smooth, rather than scabrous, panicle branches (Murray, pers com. 2005).

6. Deschampsia elongata (Hook.) Munro
Slender Hairgrass

Plants perennial; densely ces-pitose. Culms (10)30–120 cm. Leaves sometimes forming a basal tuft; sheaths glabrous; ligules 2.5–8(9) mm, acute to acuminate; blades 7–30 cm long, 0.2–2 mm wide, usually involute. Panicles 5–30(35) cm long, 0.5–1.5(2) cm wide, erect or nodding; branches erect to ascending. Spikelets 3–6.7 mm, bisexual, narrowly V-shaped, appressed to the branches. Glumes equaling or exceeding the florets, narrowly lanceolate, usually pale green, sometimes purple-tipped, 3-veined, acuminate; lower glumes (3)3.2–5.5(6.7) mm; upper glumes (3)3.1–5.4(6) mm; callus hairs 0.3–1.15 mm; lemmas 1.7–4.3 mm, smooth, shiny, glabrous, apices weakly toothed or erose, awns 1.5–5.5(6) mm, straight to slightly geniculate, attached from slightly below to slightly above the middle of the lemma, exceeding the florets by 1–2.5 mm; anthers 0.3–0.5(0.7) mm. 2n = 26.

Deschampsia elongata grows in moist to wet habitats, from near sea level to alpine elevations, from Alaska and the Yukon south to northern Mexico and east to Montana, Wyoming, and Arizona. It also grows, as a disjunct, in Chile. The records from Maine and Colorado probably represent introductions.

7. Deschampsia danthonioides (Trin.) Munro
Annual Hairgrass

Plants annual; tufted. Culms 10–40(70) cm, erect. Leaves not forming a basal tuft; ligules (0.5)2–3(4.7) mm, acute to acu-minate, entire; blades 0.3–1.5 mm wide, involute or flat. Panicles 5–15(25) cm long, 2–8 cm wide, contracted to open, erect; branches with the spikelets confined to the distal portion. Spikelets 4–9 mm, bisexual, narrowly V-shaped, usually pale green. Glumes exceeding the distal florets, glabrous to scabridulous, 3-veined; lower glumes 4–9 mm; upper glumes 3.5–8.5 mm; callus hairs 0.4–1.6 mm; lemmas 1.5–3 mm, smooth, shiny, glabrous, pale green or purplish, apices blunt, erose to 4–toothed, ciliate, awns 4–9 mm, attached from near the base to about the middle of the lemmas, strongly geniculate, geniculation above the lemma apices, distal segment 1.5–5 mm; anthers 0.3–0.5 mm. 2n = 26.

Deschampsia danthonioides grows in temperate and cool-temperate regions, usually in open, wet to dry habitats and often in disturbed ground. Its primary range extends from southern British Columbia, through Washington and Idaho, to Baja California, Mexico. It also grows, as a disjunct, in Chile and Argentina.

Records from the Yukon Territory date from the late 1800s and early 1900s; it has not been seen since in the region. Records from east of the primary region are also probably introductions; it is not known whether the species has persisted at these locations.

8. Deschampsia flexuosa (L.) Trin.
Crinkled hairgrass, Wavy Hairgrass, Deschampsie Flexueuse

Plants perennial; densely ces-pitose. Culms 30–80 cm, erect or geniculate at the base, usually with 2 nodes. Leaves mostly basal, sometimes forming a basal tuft; sheaths smooth, glab-rous; ligules 1.5–3.6 mm, round-ed to acute; blades 12–25 cm long, strongly rolled, 0.3–0.5 mm in diameter, abaxial surfaces smooth or scabridulous, glabrous or hairy, often scabridulous or hairy proximally and essentially smooth and glabrous distally, adaxial surfaces scabrous, flag leaf blades 5–8 cm. Panicles 5–15 cm long, (2)4–12 cm wide, narrow to open, often nodding; branches ascending to spreading, flexuous, smooth or scabridulous. Spikelets 4–7 mm, ovate or U-shaped. Glumes exceeded by or subequal to the adjacent florets, 1–veined, acute; lower glumes 2.7–4.5 mm; upper glumes 3.5–5 mm; callus hairs to 1 mm; lemmas 3.3–5 mm, scabridulous or puberulent, hairs to 0.1 mm, apices acute, erose to 4-toothed, awns 3.7–7 mm, attached near the base of the lemma, strongly geniculate, geniculation below the lemma apices, distal segment 2.5–4.5 mm, pale; anthers 2–3 mm. 2n = 14, 26, 28, 32, 42.

Deschampsia flexuosa grows on dry, often rocky slopes, and in woods and thickets, often in disturbed sites. In the Flora region, it is primarily eastern in distribution, with records from west of the Great Lakes and Appalachians probably being introductions. It is also known from Mexico, Central America, South America, Borneo, the Philippines, and New Zealand.