17.35   CHLORIS Sw.
Mary E. Barkworth

Plants annual or perennial; habit various, rhizomatous, stoloniferous, or cespitose. Culms 10-300 cm; internodes pith-filled. Sheaths strongly keeled, glabrous, scabrous, or pubescent; ligules membranous, erose to lacerate or ciliate, occasionally absent; blades, particularly those of the basal leaves, often with long, coarse hairs near the base of the adaxial surface and margins. Inflorescences terminal, panicles with (1)5-30 spikelike branches, these usually borne digitately, occasionally in 2-several whorls, sometimes with a few isolated branches below the primary whorl(s), all branches usually exceeding the upper leaves; branches with spikelets in 2 rows on 1 side of the branch axes. Spikelets solitary, sessile to pedicellate, laterally compressed, with 2-3(5) florets, usually only the lowest floret bisexual, rarely the lower 2 florets bisexual, remaining floret(s) sterile or staminate; florets laterally compressed or terete, cylindrical to obovoid, awned or unawned, sterile and staminate florets progressively reduced distally if more than 1 present; disarticulation usually beneath the lowest floret in the spikelets, all florets falling as a unit, sometimes at the uppermost cauline node, panicles falling intact. Glumes unequal, exceeded by the florets, lanceolate, acute to acuminate, usually unawned, occasionally awned, awns to 0.3 mm; calluses bearded; lemmas of bisexual florets 3-veined, marginal veins pubescent, midveins usually glabrous, sometimes scabrous, usually extending into an awn, sometimes merely mucronate, awns to 37 mm, lemma apices truncate or obtuse, entire or bilobed, lobes, when present, sometimes awn-tipped, awns to 0.6 mm; paleas shorter than the lemmas, 2-veined, veins scabrous; anthers 3; lodicules 2. Caryopses ovoid, elliptic, or obovoid. x = (9)10. Named for Chloris, the Greek goddess of flowers.

As interpreted here, Chloris is a tropical to subtropical genus of 55-60 species. It is most abundant in the Southern Hemisphere. Of the 18 species treated here, 11 are native, five are species that have been collected in the Flora region but seem not to have persisted, one is an introduced species that has become established, and one is known only from cultivation. Many species of Chloris, including the native species, provide good forage.

Anderson (1974) interpreted Chloris as including Enteropogon, Eustachys, and Trichloris. Support for treating the genus more narrowly can be found in Van den Borre (1994; 2000) and Hilu and Alice (2001), but the limits of many genera in the Cynodonteae, including Chloris, are not clear.


SELECTED REFERENCES Anderson, D.E. 1974. Taxonomy of the genus Chloris (Gramineae). Brigham Young Univ. Sci. Bull., Biol. Ser. 19:1-133; Hilu, K.W. and L.A. Alice. 2001. A phylogeny of the Chloridoideae (Poaceae) based on matK sequences. Syst. Bot. 26:386-405; Hitchcock, A.S. 1951 [title page 1950]. Manual of the Grasses of the United States, ed. 2, rev. A. Chase. U.S.D.A. Miscellaneous Publication No. 200. U.S. Government Printing Office, Washington, D.C., U.S.A. 1051 pp.; Van den Borre, A. 1994. A taxonomy of the Chloridoideae (Poaceae), with special reference to the genus Eragrostis. Ph.D. dissertation, Australian National University, Canberra, New South Wales, Australia. 313 pp.; Van den Borre, A. and L. Watson. 2000. On the classification of the Chloridoideae: Results from morphological and leaf anatomical data analyses. Pp. 180-183 in S.W.L. Jacobs and J. Everett (eds.). Grasses: Systematics and Evolution. International Symposium on Grass Systematics and Evolution (3rd:1998). CSIRO Publishing, Collingwood, Victoria, Australia. 408 pp.

1
Panicle branches tightly entangled for most of their length, separable only with difficulty and forming a cylindrical, spikelike inflorescence, the individual branches visibly distinct only at the tip ..... 1. C. berroi
Panicle branches sometimes appressed to each other but easily separable, inflorescences evidently composed of multiple spikelike branches borne in 1-several whorls (2)
2
Panicles with 1-3 branches (3)
Panicles with 4 or more branches (6)
3
Lowest (bisexual) lemmas usually glabrous or scabrous, occasionally with a few scattered hairs on the margins (4)
Lowest (bisexual) lemmas conspicuously hairy on the margins and keels (5)
4
Lemma of the first sterile floret in each spikelet entire; panicle branches 5-11 cm long, with about 10 spikelets per cm ..... 9. C. ventricosa
Lemma of the first sterile floret in each spikelet bilobed for 1/3-1/2 of its length; panicle branches 4-17 cm long, with 3-7 spikelets per cm on the distal portion ..... 11. C. divaricata
5
Lemma of the lowest (bisexual) floret in each spikelet 1.8-2.8 mm long ..... 2. C. ciliata
Lemma of the lowest (bisexual) floret in each spikelet 2.7-4.2 mm long ..... 3. C. canterae
6
Spikelets with 3 or more florets (the third often concealed), the lowest (first) floret bisexual, the remainder sterile or staminate, the terminal floret sometimes represented only by a clavate rachilla segment (7)
Spikelets with 2 florets, 1 bisexual and 1 sterile or staminate (16)
7
Second sterile florets ovoid to subspherical, strongly inflated; first sterile florets 0.9-1.3 mm long ..... 5. C. barbata
Second sterile florets widened or not distally, not inflated or inflated only near the apices; first sterile florets 1-3.5 mm long (8)
8
All sterile or staminate florets awned (9)
At least 1 of the sterile or staminate florets in each spikelet unawned (10)
9
Culms to 300 cm tall; panicle branches averaging 10 spikelets per cm; spikelets tawny ..... 8. C. gayana
Culms 30-50 cm tall; panicle branches averaging 6 spikelets per cm; spikelets dark brown to black ..... 10. C. truncata
10
Spikelets barely imbricate, averaging 5-7 per cm; plants annual or short-lived perennials ..... 6. C. pilosa
Spikelets strongly imbricate, averaging 10-14 per cm; plants perennial or annual (11)
11
Margins of the lowest lemma in each spikelet scabrous, glabrous, or appressed pubescent ..... 8. C. gayana
Margins of the lowest lemma in each spikelet conspicuously hairy, at least distally, the hairs 0.5-3 mm long (12)
12
Plants annual; third florets, if present, shorter than the subtending rachilla segment ..... 7. C. virgata
Plants perennial; third florets as long as or longer than the subtending rachilla segment (13)
13
Lowest lemmas 2.7-4.2 mm long ..... 3. C. canterae
Lowest lemmas 1.5-2.8 mm long (14)
14
Panicles with 2-7 branches; branches 3.5-8 cm long; awns of the first sterile florets 0.9-1.4 mm long ..... 2. C. ciliata
Panicles with (4)8-30 branches; branches (5)8-20 cm long; awns of the first sterile florets 0.8-4 mm long (15)
15
First sterile florets 1-1.6 mm long ..... 4. C. elata
First sterile florets 2.2-3.2 mm long ..... 8. C. gayana
16
Lemmas of the sterile or staminate florets bilobed for at least 1/3 of their length; lateral lobes sometimes awned (17)
Lemmas of the sterile or staminate florets not bilobed or lobed less than 1/4 of their length; lateral lobes, if present, not awned (18)
17
Spikelets pectinate, diverging from the branch axes, crowded, averaging 10-14 per cm; plants annual ..... 12. C. pectinata
Spikelets appressed to the branch axes, not crowded, averaging 3-7 per cm; plants perennial ..... 11. C. divaricata
18
Lowest (bisexual) lemmas unawned, mucronate, or shortly awned, the awns less than 1.5 mm long (19)
Lowest (bisexual) lemmas always awned, the awns 1.5-16 mm long (24)
19
Plants annuals or short-lived perennials, sometimes shortly stoloniferous ..... 6. C. pilosa
Plants perennial, sometimes stoloniferous (20)
20
Lowest (bisexual) lemmas unawned, sometimes mucronate, the mucros to 1 mm long (21)
Lowest (bisexual) lemmas always awned, the awns 1-11 mm long (22)
21
Sterile or staminate florets inflated, 1-1.5 mm wide and about equally long ..... 13. C. cucullata
Sterile or staminate florets 0.3-0.9 mm wide, usually at least twice as long ..... 17. C. submutica
22
Panicles with 2-9 branches; branches 5-11 cm long ..... 9. C. ventricosa
Panicles with 4-28 branches (usually more than 8); branches 2-20 cm long (23)
23
Panicle branches 10-20, 2-5 cm long; spikelets with only 1 sterile floret ..... 13. C. cucullata
Panicle branches 4-28 (usually more than 8), 5-20 cm long, spikelets usually with 2 sterile florets, the lowest often enclosing and concealing the second ..... 4. C. elata
24
Lowest lemmas with a conspicuous glabrous or pubescent groove on each side; plants annual or short-lived perennials ..... 6. C. pilosa
Lowest lemmas not conspicuously grooved on the sides; plants perennial or annual (25)
25
Margins of the lowest (bisexual) lemmas conspicuously hairy along most of their length, the hairs strongly divergent, at least some longer than 1 mm (26)
Margins of the lowest (bisexual) lemmas glabrous, scabrous, or appressed pubescent, sometimes with a few scattered longer hairs, or with strongly divergent hairs distally but not basally (27)
26
Plants rarely stoloniferous; second (first sterile) florets 1-1.6 mm long ..... 4. C. elata
Plants usually stoloniferous; second (first sterile) florets 2.2-3.2 mm long ..... 8. C. gayana
27
Panicle branches borne in 2 or more, clearly distinct whorls (28)
Panicle branches usually digitate, in a single terminal cluster, sometimes with a poorly-developed second whorl just below the terminal cluster (30)
28
Second (first sterile) florets 0.4-0.7 mm long ..... 18. C. radiata
Second (first sterile) florets 0.9-2.5 mm long (29)
29
Panicle branches spikelet-bearing to the base; panicles with 10-16 branches, these usually in several, well separated whorls below a solitary, vertical branch ..... 14. C. verticillata
Panicle branches naked on the basal 2-5 cm; panicles with 8-10 branches, these usually digitate, sometimes a second whorl present below the terminal whorl ..... 16. C. texensis
30
Margins of the lowest (bisexual) lemmas with conspicuously longer hairs distally than basally, the distal hairs usually more than 1.5 mm long (31)
Margins of the lowest (bisexual) lemmas glabrous or with appressed hairs less than 1 mm long, occasionally with a few scattered longer hairs (32)
31
Plants annual; third floret, if present, shorter than its subtending rachilla segment ..... 7. C. virgata
Plants perennial; third floret, if present, longer than its subtending rachilla segment ..... 8. C. gayana
32
Panicle branches without spikelets on the basal 2-5 cm ..... 16. C. texensis
Panicle branches spikelet-bearing to the base or naked for less than 2 cm (33)
33
Second florets (first sterile florets) 0.1-0.5 mm wide (34)
Second florets (first sterile florets) 0.5-1 mm wide (36)
34
Plants annual, sometimes rooting at the lower nodes, not stoloniferous; second florets 0.4-0.7 mm long ..... 18 C. radiata
Plants perennial, not rooting at the lower nodes but sometimes stoloniferous; second florets 0.7-2.6 mm long (35)
35
Culms 10-40 cm; lowest lemmas 1.9-2.7 mm long with awns 1.9-5.2 mm long; second florets 0.9-1.7 mm long ..... 15. C. andropogonoides
Culms to 100 cm; lowest lemmas 2-5.4 mm long, with awns 1-11 mm long; second florets 1-2.6 mm long ..... 9. C. ventricosa
36
Lemmas of the second florets inconspicuously bilobed; spikelets with (1)2-4 staminate or sterile florets ..... 8. C. gayana
Lemmas of the second florets usually not bilobed; spikelets with 1(2) staminate or sterile florets (37)
37
Panicle branches 5-23 cm long; margins of the lowest lemmas appressed pubescent, occasionally sparsely so; second florets awned, the awns 3.1-12.5 mm long; blades without basal hairs ..... 10. C. truncata
Panicle branches 5-11 cm long; margins of the lowest lemmas usually glabrous or scabrous, occasionally sparsely pubescent; second florets awned, the awns 0.5-7.5 mm long; blades with basal hairs up to 3 mm long ..... 9. C. ventricosa


1.   Chloris berroi Arechav.

Plants perennial; cespitose. Culms 15-80 cm. Sheaths glabrous; ligules ciliate; blades 3-15 cm long, 1.5-2 mm wide, glabrous or sparsely pilose near the base. Panicles with 2-4 branches, these entangled for most of their length, separable only with difficulty, forming a narrow, cylindrical, spikelike inflorescence, individual branches visibly distinct only at the tips; branches 3-12 cm, tightly appressed and adherent, with 9-12 spikelets per cm. Spikelets imbricate, with 1 bisexual and 3 sterile florets. Lower glumes 1.5-2 mm long, about 0.3 mm wide; upper glumes 2.1-2.6 mm long, 0.3-0.6 mm wide; lowest lemmas 2.7-3.5 mm, ovate, margins and keels hairy, hairs to 2 mm, awns 2.7-3.4 mm; second florets about 1.9 mm, glabrous, awned; distal florets unawned. Caryopses 1.2-1.8 mm long, 0.5-0.7 mm wide, trigonous. 2n= 40.

Chloris berroi is native to the Rio de la Plata region of Argentina and Uruguay. It has been cultivated at scattered locations in the United States (Hitchcock 1951), but is not known to be established in the Flora region.


2.   Chloris ciliata Sw.
Fringed Windmill-Grass

Plants perennial; cespitose. Culms 25-60 cm, erect. Sheaths glabrous; ligules absent or 0.3-0.4 mm, ciliate; blades 10-20 cm long, about 5 mm wide, sometimes with long basal hairs, otherwise glabrous or scabrous. Panicles digitate, with 2-5(7) evidently distinct branches; branches 3.5-6(8) cm, ascending to spreading. Spikelets imbricate, with 1 bisexual and 2 sterile florets. Lower glumes 1.3-1.7 mm; upper glumes 2-2.5 mm; lowest lemmas 1.8-2.8 mm long, 0.8-1.1 mm wide, strongly laterally compressed, elliptic, margins and keels conspicuously hairy, hairs 0.5-1.5 mm, apices awned, awns 0.9-1.4 mm; second florets 1.3-1.8 mm long, 0.8-1.8 mm wide, widened distally, not inflated, truncate, enclosing the distal florets, awned, awns 0.9-1.4 mm; distal florets 0.8-1.1 mm long, 0.9-1.2 mm wide, aslong as or longer than the subtending rachilla internodes, unawned. Caryopses about 1.4 mm long, 0.7 mm wide. 2n = 40.

Chloris ciliata is a native species of grasslands from the Gulf Coast of Texas, through the Caribbean islands and Mexico to Central America, then, as a disjunct, in Argentina. Argentinean plants differ from northern plants in having long hairs associated with their basal ligules, but no other differences are known. It has been found, as an introduction, in New York.


3.   Chloris canterae Arechav.
Paraguayan Windmill-Grass

Plants perennial; cespitose. Culms to 100 cm, erect. Sheaths glabrous; ligules about 0.5 mm, membranous, erose; blades to 25 cm long, 1-6 mm wide, flat or involute, sometimes appearing filiform, bases with hairs to 7 mm. Panicles digitate, with 2-9 evidently separate branches; branches 3-14 cm, erect to curving, averaging 11 spikelets per cm. Spikelets strongly imbricate, light to medium brown, with 2(3) sterile florets. Lower glumes 1.6-2.4 mm; upper glumes 2.3-3.8 mm; lowest lemmas 2.7-4.2 mm long, 0.6-1.1 mm wide, marginal veins and keels densely and conspicuously hairy, hairs 1.5-3 mm, awns 2.4-5.5 mm; second florets 1.1-1.8 mm, about 1/2 as wide as long, conspicuously widened distally, laterally compressed, glabrous, truncate, awned, awns 1.5-3.5 mm; distal sterile floret(s) similar but smaller, longer than the subtending rachilla internodes, unawned. Caryopses 1.3-2 mm long, 0.8-0.9 mm wide, ovoid-ellipsoid.

Chloris canterae is native to South America. Both of its varieties are found in the coastal plain of Texas and Louisiana. In South America, they are essentially sympatric, but occupy different habitats.

1
Leaves primarily cauline, 2.5-6 mm wide, flat; panicle branches 4-14 cm long ..... var. canterae
Leaves primarily basal, 1-1.5 mm wide, involute; panicle branches 3-6 cm long ..... var. grandiflora


Chloris canterae Arechav. var. canterae

Plants loosely cespitose. Culms to 100 cm. Leaves primarily cauline; blades 2.5-6 mm wide, flat. Panicles with 2-9 branches; branches (4)5-14 cm. 2n = 36.

Chloris canterae var. canterae has been collected in Texas and Louisiana. In South America, it grows on moist soils of the campo in Paraguay, southern Brazil, and northeastern Argentina.


Chloris canterae var. grandiflora (Roseng. & Izag.) D.E. Anderson

Plants densely cespitose. Culms 5-30 cm. Leaves primarily basal, 1-1.5 mm wide, involute. Panicles with 3-5 branches; branches 3-6 cm. 2n = unknown.

Chloris canterae var. grandiflora was collected around woolen mills in southeastern North America in the nineteenth and early twentieth centuries. It has also been found in Texas, but less frequently than var. canterae. In South America, it grows in drier, more rocky areas than var. canterae.


4.   Chloris elata Desv.
Tall Windmill-Grass

Plants perennial; usually cespitose, rarely stoloniferous. Culms to 135 cm. Sheaths mostly glabrous; ligules 0.7-1 mm, erose to lacerate; blades to 45 cm long, to 15 mm wide, with basal hairs, otherwise usually glabrous, occasionally scabrous. Panicles digitate, with (4)8-28 evidently distinct and easily separable branches; branches (5)8-20 cm, flexible, usually more or less spreading, sometimes drooping, averaging 12 spikelets per cm. Spikelets strongly imbricate, with 1 bisexual and usually 2 sterile florets. Lower glumes 1-2.5 mm; upper glumes 1.9-3.5 mm; lowest lemmas 1.5-2.8 mm long, 0.5-0.9 mm wide, elliptic, strongly laterally compressed, margins conspicuously hairy for most of their length, hairs 1-3 mm, strongly divergent, keels densely appressed pubescent, not or only minutely bilobed, apices awned, awns 1.4-4.8 mm; second florets 1-1.6 mm, cylindrical to narrowly turbinate, shortly bilobed, lobes less than 1/5 as long as the lemmas, awned from the sinuses, awns 1.7-4 mm; third florets often enclosed by the first sterile florets, 0.5-0.9 mm, turbinate or flabellate, as long as or longer than the subtending rachilla internodes, sometimes inflated apically, unawned. Caryopses about 1 mm long, about 0.5 mm wide. 2n = 72.

The range of Chloris elata lies primarily to the south of the Flora region, extending from southern Florida and the Caribbean islands to Peru and Argentina.


5.   Chloris barbata Sw.
Swollen Windmill-Grass

Plants annual. Culms 15-95 cm, erect or decumbent and rooting at the lower nodes. Sheaths glabrous; ligules 0.3-0.5 mm, erose to lacerate; blades to 15 cm long, 0.3-0.6 mm wide, with basal hairs, otherwise usually glabrous. Panicles digitate, with 7-15 evidently distinct branches; branches 3-8 cm, more or less erect, averaging 14 spikelets per cm. Spikelets with 1 bisexual and 2(3) sterile florets. Lower glumes 1.2-2.1 mm; upper glumes 2.3-2.7 mm; lowest lemmas 2-2.7 mm, ovate to elliptic, calluses and distal portion of the margins pilose, hairs to 1 mm, keels glabrous or pilose, apices awned, awns 4-7.7 mm; second florets 0.9-1.3 mm long, 0.4-0.9 mm wide, slightly to strongly widened distally, inflated, usually glabrous, truncate, awned, awns 5-7 mm; third florets obovoid to subspherical, smaller than the first, strongly inflated. Caryopses 1.1-1.4 mm. 2n = 20, 40, ca. 50.

Chloris barbata grows in subtropical and tropical coastal regions on loams, limestone-derived soils, and along beaches. The main portion of its range lies to the south of the Flora region, through the Caribbean and the east coast of Mexico, Central America, and South America. It is a weedy species, often growing in waste areas, but also in cultivated fields.


6.   Chloris pilosa Schumach.

Plants annual or short-lived perennials; sometimes shortly stoloniferous. Culms 30-70(200) cm, erect or somewhat decumbent. Sheaths glabrous or sparsely to densely pilose; blades to 30 cm long, 2-10 mm wide, with coarse hairs behind the ligule and on the lower portion of the margins. Panicles digitate, with 5-9 clearly distinct or easily separable branches; branches 3-5 cm, with 5-7 spikelets per cm. Spikelets barely imbricate, pale to dark gray, often mottled when mature, with 1 bisexual and (1)2 sterile florets. Lower glumes 1.1-1.6 mm; upper glumes 1.9-2.3 mm, awned, awns to 0.3 mm; lowest lemmas 2.3-3.5 mm, broadly ovate or elliptic, keels gibbous, sides with a conspicuous glabrous or pubescent groove, margins glabrous or appressed pubescent, apices awned, awns to 6 mm; second florets 1.5-2.2 mm, widened and inflated distally, mucronate or awned, awns to 3 mm; distal florets less than 1 mm, turbinate; anthers 0.4-0.5 mm. Caryopses 1.3-1.5 mm long, 0.5-0.6 mm wide, trigonous. 2n = 20, 30.

Chloris pilosa is native to equatorial Africa, but it is sometimes planted for forage. It has been collected in Kleberg County, Texas, possibly from an experimental forage planting; it is not known to be established in the Flora region.


7.   Chloris virgata Sw.
Feather Windmill-Grass, Feather Fingergrass

Plants annual; usually tufted, occasionally stoloniferous. Culms 10-100+ cm. Sheaths usually glabrous; ligules to 4 mm, erose or ciliate; blades to 30 cm long, to 15 mm wide, basal hairs to 4 mm, otherwise usually glabrous, occasionally pilose. Panicles digitate, with 4-20, evidently distinct branches; branches 5-10 cm, erect to ascending, averaging 10 spikelets per cm. Spikelets strongly imbricate, with 1 bisexual and 1(2) sterile floret(s). Lower glumes 1.5-2.5 mm; upper glumes 2.5-4.3 mm; lowest lemmas 2.5-4.2 mm, keels usually prominently gibbous, glabrous, or conspicuously pilose, sides not grooved, margins glabrous, scabrous or pilose basally, with conspicuously longer hairs distally, hairs longer than 1.5 mm, lemma apices not conspicuously bilobed, awned, awns 2.5-15 mm; second florets 1.4-2.9 mm long, 0.4-0.8 mm wide, somewhat widened distally, not inflated, bilobed, lobes less than 1/5 as long as the lemmas, awned from the sinuses, awns 3-9.5 mm; third florets greatly reduced, unawned and shorter than the subtending rachilla segment or absent but the rachilla segment present. Caryopses 1.5-2 mm long, about 0.5 mm wide, elliptic. 2n = 20, 26, 30, 40.

Chloris virgata is a widespread species that grows in many habitats, from tropical to temperate areas with hot summers, including much of the United States. It is a common weed in alfalfa fields of the southwestern United States.


8.   Chloris gayana Kunth
Rhodesgrass

Plants perennial; usually stoloniferous. Culms to 300 cm, erect. Sheaths glabrous or scabrous, often ciliate apically; ligules ciliate; blades to 30 cm long, 15 mm wide, scabrous. Panicles digitate, with 9-30 evidently distinct branches; branches 8-20 cm, usually somewhat divaricate, spikelet-bearing to the base, averaging 10 spikelets per cm. Spikelets strongly imbricate, tawny, with 1 bisexual and (1)2-4 usually staminate, sometimes sterile florets. Lower glumes 1.4-2.8 mm; upper glumes 2.2-3.5 mm; lowest lemmas 2.5-4.2 mm long, 0.7-1 mm wide, ovate to obovate or elliptic, somewhat gibbous, sides not grooved, pubescence variable, sides usually glabrous, sometimes scabrous or appressed pubescent, margins usually glabrous or appressed pubescent on the lower portions, sometimes throughout their length, sometimes with strongly divergent hairs distally, occasionally with strongly divergent hairs their entire length, divergent hairs, when present, 1+ mm, lemma apices inconspicuously bilobed, awned, awns 1.5-6.5 mm; second florets staminate or sterile, 2.2-3.2 mm long, 0.3-1 mm wide, similar to the first floret but more cylindrical, not widened distally, inflated, if at all, only near the apices, inconspicuously bilobed, awned, awns 0.8-3.2 mm; distal florets progressively smaller, longer than the subtending rachilla segment, awn-tipped or unawned. Caryopses 1-1.5 mm long, about 0.5 mm wide. 2n = 20, 30, 40.

Chloris gayana grows in warm-temperate to tropical regions throughout the world, including the southern United States. It is cultivated as a meadow grass in irrigated regions of the southwest.


9.   Chloris ventricosa R. Br.
Plump Windmill-Grass

Plants perennial; stoloniferous. Culms to 100 cm, erect. Sheaths glabrous, scabrous, or partly pilose; ligules erose to ciliate; blades with basal hairs to 3 mm, otherwise glabrous, scabrous, or sparsely pilose. Panicles digitate, with 2-9 evidently distinct branches; branches 5-11 cm, spikelet-bearing almost to the base, averaging 10 spikelets per cm. Spikelets with 1 bisexual and 1(2) staminate floret(s). Lower glumes 1.2-2.3 mm; upper glumes 2.5-4.1 mm; lowest lemmas 2-5.4 mm long, 0.6-1.2 mm wide, elliptic to obovate, sometimes ventricose, usually glabrous, midveins scabrous, sides not conspicuously grooved, margins inrolled, usually glabrous or scabrous, occasionally with a few scattered hairs, especially distally, apices entire or minutely bilobed, awned, awns 1-11 mm; second florets 1-2.6 mm long, 0.3-1 mm wide, cylindrical to narrowly turbinate, apices obtuse to truncate, entire, awned, awns 0.5-7.5 mm; anthers 0.7-1.4 mm. Caryopses 1.5-2.1 mm long, about 0.4 mm wide, narrowly obovoid to trigonous. 2n = unknown.

Chloris ventricosa, an Australian species, has been found near old woolen mills in South Carolina and has been cultivated. It is very similar to C. truncata, but usually has shorter panicle branches. Other differences include its usually tawny bisexual lemmas and their usually glabrous margins.


10.   Chloris truncata R. Br.
Black Windmill-Grass

Plants perennial; stoloniferous. Culms 30-50 cm. Sheaths glabrous; ligules short-ciliate; blades 9-17 cm long, 0.2-0.3 mm wide, without basal hairs, glabrous, sometimes scabrous. Panicles digitate, with 5-13 clearly distinct branches; branches 5-23 cm, spikelet-bearing to the base or within 1 cm of the base, averaging 6 spikelets per cm elsewhere. Spikelets dark brown to black, with 1 bisexual and 1(2) staminate floret(s). Lower glumes 1.4-2.3 mm; upper glumes 2.8-4.2 mm; lowest lemmas 1.8-4.5 mm long, 0.2-0.7 mm wide, narrowly elliptic, becoming very dark, often almost black at maturity, sides not grooved, mostly glabrous but the margins appressed pubescent, sometimessparsely so, hairs shorter than 1 mm, apices truncate, awned, awns 3.1-16 mm; second florets 1.3-3.5 mm long, 0.5-0.9 mm wide, not inflated, truncate, not or only minutely bilobed, awned, awns 3.1-12.5 mm; anthers about 0.6 mm. Caryopses 1.7-2.2 mm long, 0.3-0.5 mm wide, ellipsoid to narrowly obovate, trigonous. 2n = 40.

Chloris truncata, like the rather similar C. ventricosa, is an Australian native that has been found near woolen mills in South Carolina and beside a road near Lake Skinner in Riverside County, California. It usually differs from C. ventricosa in having longer panicle branches. Other differences include its very dark, almost black, bisexual lemmas and their usually appressed pubescent margins.


11.   Chloris divaricata R. Br.
Spreading Windmill-Grass

Plants perennial; cespitose to shortly stoloniferous. Culms 20-50 cm. Sheaths glabrous; ligules membranous, ciliolate; blades to 15 cm long, 1-1.5 mm wide, glabrous or scabrous. Panicles digitate, with 3-9 branches; branches 4-17 cm, evidently distinct, becoming horizontal, spikelet-bearing to the base or within 0.5 cm of the base, distal portion with 3-7 spikelets per cm. Spikelets appressed, with 1 bisexual and 1 sterile floret. Lower glumes 0.9-1.8 mm; upper glumes 2-2.9 mm; lowest lemmas 2.9-4 mm, linear to narrowly lanceolate, mostly glabrous or scabrous, margins glabrous or with a few short, appressed hairs near the apices, 1-3-awned, central awns 7.5-17 mm, lateral lobes unawned or with awns less than 0.4 mm; second florets 1.2-1.9 mm, narrowly elliptic, bilobed for 1/3-1/2 of their length, apices acute, awned from between the lobes, awns 4.5-9.5 mm. Caryopses about 2.2 mm long, about 0.4 mm wide, narrowly ellipsoid. 2n = unknown.

Chloris divaricata is an Australian species that was collected around woolen mills of South Carolina in the first half of the twentieth century. It has since become established in Texas and New Mexico.


12.   Chloris pectinata Benth.
Comb Windmill-Grass

Plants annual. Culms 20-75 cm, erect, often branched above. Sheaths glabrous; ligules membranous, ciliate; blades to 15 cm long, 2-5 mm wide, sometimes with basal hairs, otherwise glabrous or scabrous. Panicles digitate, with 4-13 easily separable or evidently distinct branches; branches 5-11 cm, initially erect, becoming divaricate, with 10-14 spikelets per cm. Spikelets pectinate, diverging at a wide angle from the branch axes, with 1 bisexual and 1 staminate floret. Lower glumes 1.4-2.5 mm; upper glumes 2.9-4.3 mm; lowest lemmas 3-6.2 mm long, 0.4-0.6 mm wide, linear to narrowly lanceolate, margins glabrous, scabrous, or with hairs less than 0.2 mm, lemma apices bilobed, lobes 0.5-1 mm, sometimes awned, central awns 4-37 mm, awns of lateral lobes, if present, less than 0.6 mm; second florets 1.7-2.9 mm long, 0.2-0.3 mm wide, laterally compressed, bilobed, lobes 1/3-1/2 as long as the lemmas, awned, awns 4-10 mm. Caryopses about 2.3 mm long, about 0.3 mm wide, narrowly ellipsoid, trigonous. 2n = unknown.

Chloris pectinata is an Australian species that was collected around woolen mills in South Carolina in the first half of the twentieth century.


13.   Chloris cucullata Bisch.
Hooded Windmill-Grass

Plants perennial; cespitose. Culms 15-60 cm, erect. Sheaths glabrous; ligules 0.7-1 mm; blades to 20 cm long, 2-4 mm wide, without basal hairs, glabrous or scabrous, upper cauline leaves often greatly reduced. Panicles with 10-20 branches in several closely-spaced whorls; branches 2-5 cm, spreading, with 14-18 spikelets per cm; disarticulation beneath the glumes. Spikelets with 1 bisexual and 1 sterile floret. Lower glumes 0.5-0.7 mm; upper glumes 1-1.5 mm; lowest lemmas 1.5-2 mm long, 0.7-1 mm wide, broadly elliptic, mostly glabrous but the keels and marginal veins appressed-pilose, obtuse, awned, awns 0.3-1.5 mm; second florets 1-1.5 mm long and about equally wide, conspicuously inflated, spherical, with the distal portion of the margins inrolled, not or inconspicuously bilobed, lobes less than 1/5 as long as the lemmas, midveins sometimes excurrent to 1.5 mm. Caryopses 0.9-1.2 mm long, about 0.5 mm wide, obovoid. 2n = 40.

Chloris cucullata is common along roadsides and in waste areas throughout much of Texas and adjacent portions of New Mexico and Mexico. Records from outside this area probably represent introductions. Chloris cucullata hybridizes with both C. andropogonoides and C. verticillata (see discussion under C. andropogonoides).


14.   Chloris verticillata Nutt.
Tumble Windmill-Grass

Plants perennial; cespitose. Culms 14-40 cm, erect or decumbent, sometimes rooting at the lower nodes. Sheaths mostly glabrous, with hairs to 3 mm adjacent to the ligule; ligules 0.7-1.3 mm, shortly ciliate; blades to 15 cm long, 2-3 mm wide, with basal hairs, otherwise glabrous or scabrous. Panicles with 10-16, evidently distinct branches in several well-separate whorls, and a solitary, vertical terminal branch; branches 5-15 cm, spikelet-bearing to the base, with 4-7 spikelets per cm; disarticulation at the uppermost cauline node, panicles falling intact. Spikelets with 1 bisexual and 1 sterile floret. Lower glumes 2-3 mm; upper glumes 2.8-3.5 mm; lowest lemmas 2-3.5 mm long, 1.5-1.9 mm wide, elliptic to lanceolate, keels glabrous or appressed pubescent, sides not conspicuously grooved, margins glabrous or appressed pubescent, acute to obtuse, awned, awns 4.8-9 mm; second florets 1.1-2.3 mm, oblong, somewhat inflated, truncate, not or inconspicuously bilobed, lobes less than 1/5 as long as the lemmas, midveins excurrent, forming 3.2-7 mm awns. Caryopses 1.3-1.5 mm long, about 0.5 mm wide, elliptic. 2n = ca. 28, 40, 63.

Chloris verticillata is a common weed of roadsides, lawns, and waste areas in the central United States. Prior to disruption of the native vegetation, it grew in low areas of the central prairies. It also grows in northern Mexico. Chloris verticillata hybridizes with both C. cucullata and C. andropogonoides (see discussion under C. andropogonoides).


15.   Chloris andropogonoides E. Fourn.
Slimspike Windmill-Grass

Plants perennial; cespitose to shortly stoloniferous. Culms 10-40 cm. Sheaths glabrous; ligules 0.5-0.8 mm, shortly ciliate; blades to 15 cm long, to 1 mm wide, sometimes with basal hairs, mostly glabrous or scabrous. Panicles with 6-13, evidently distinct branches, these usually digitate, sometimes with a second, poorly-developed whorl just below the terminal branches; branches 4-14 cm, spreading, spikelet-bearing to the base, with 4-7 spikelets per cm; disarticulation at the uppermost cauline node, panicles falling intact. Spikelets with 1 bisexual and 1 sterile floret. Lower glumes 2-2.3 mm; upper glumes 3-3.3 mm; lowest lemmas 1.9-2.7 mm long, 0.5-0.6 mm wide, lanceolate to elliptic, without conspicuous grooves on the sides, mostly glabrous but the margins and keels appressed pubescent with hairs less than 1 mm, apices acute, awned, awns 1.9-5.2 mm; second florets 0.9-1.7 mm, 0.2-0.5 mm wide, narrowly cylindrical, obtuse, bilobed and awned, lobes less than 1/5 as long as the lemmas, awns 2.5-3.5 mm. Caryopses 1.3-1.4 mm long, about 0.4 mm wide, ellipsoid. 2n = 40.

Chloris andropogonoides grows along grassy roadsides and prairie relicts of the coastal plain of southern Texas and northeastern Mexico.


Hybridization and introgression between Chloris cucullata, Chloris verticillata, and Chloris andropogonoides

Anderson (1974, pp. 97-103) noted that Chloris cucullata, C. verticillata, and C. andropogonoides are sympatric in southern and central Texas, and often form mixed populations that include many apparent hybrids and introgressants. These plants combine the morphological features of their parents and often have highly irregular meiosis. Diploid counts of about 60 are common in some populations, but seed set is high even in populations with a high level of meiotic irregularity, suggesting apomixis. In some populations, no pureparental plants are found, eliminated either through competition or hybridization. Some of the morphologically-distinct members of such hybrid complexes have been given formal names but, because morphologically-similar hybrids can have different origins, these names do not reflect true taxonomic entities. Among such names are C. brevispica Nash, C. verticillata var. aristulata Torr. & A. Gray, C. verticillata var. intermdia Vasey, C. latisquamea Nash, and C. subdolichostachya Müll.-Hal. Plants belonging to such complexes are best named as hybrids between their parents, e.g. "Chloris verticillata × C. andropogonoides", or as being close to one of the probable parents, e.g., "close to Chloris andropogonoides E. Fourn."


16.   Chloris texensis Nash
Texas Windmill-Grass

Plants perennial; cespitose. Culms 30-45 cm. Sheaths glabrous or sparsely pilose; ligules membranous, not or only shortly ciliate; blades to 15 cm long, about 4 mm wide, scabrous. Panicles with 8-10 clearly separate branches, these usually digitate, occasionally a poorly-developed second whorl present just below the terminal whorl; branches to 20 cm, divergent, basal 2-5 cm without spikelets, averaging 3-4 spikelets per cm elsewhere. Spikelets with 1 bisexual and 1 sterile floret. Lower glumes 2.7-3 mm; upper glumes 3.5-3.8 mm; lowest lemmas 3.7-4.3 mm long, 0.7-0.8 mm wide, lanceolate to narrowly ovate, sides not conspicuously grooved, margins glabrous or sparsely appressed pubescent distally with hairs shorter than 1 mm, apices acute, awned, awns 7-11 mm; second florets 2-2.5 mm long, about 0.5 mm wide, narrowly elliptic, acute, inconspicuously bilobed, awns 4.5-6.5 mm. Caryopses about 2.3 mm long, about 0.5 mm wide, ellipsoid, trigonous. 2n = unknown.

Chloris texensis appears to be rare. It is endemic to Texas.


17.   Chloris submutica Kunth
Mexican Windmill-Grass

Plants perennial; usually cespitose, occasionally shortly stoloniferous. Culms 30-75 cm, erect. Sheaths glabrous; ligules about 0.5 mm, shortly ciliate; blades to 20 cm long, to 5 mm wide, sometimes with long basal hairs, otherwise scabrous. Panicles with 5-17, evidently distinct branches in 1-3 closely-spaced whorls; branches to 7 cm, usually erect when young, spreading to reflexed at maturity, averaging 12 spikelets per cm. Spikelets with 1 bisexual and 1 staminate floret. Lower glumes 1.5-3.2 mm; upper glumes 2.5-3.4 mm; lowest lemmas 2.8-3.7 mm long, 0.6-1.1 mm wide, broadly linear to elliptic, mostly glabrous but the margins appressed pubescent, apices obtuse, not conspicuously bilobed, sometimes shortly mucronate; second florets 1.4-2.2 mm long, 0.3-0.9 mm wide, usually at least twice as long as wide, not lobed, unawned, occasionally mucronate. Caryopses 1.7-2.3 mm long, 0.5-0.6 mm wide, ellipsoid. 2n = ca. 65, 80.

Chloris submutica grows from the southwestern United States through Mexico, Guatemala, and Colombia to Venezuela. In Mexico, it is generally found between 1000-2100 m.


18.   Chloris radiata (L.) Sw.
Radiate Windmill-Grass

Plants annual; with dense fibrous root growth, not stoloniferous. Culms 30-60 cm, erect or decumbent, occasionally rooting at the lower nodes. Sheaths usually glabrous, occasionally pilose; ligules membranous, shortly ciliate; blades 10-30 cm long, to 10 mm wide, sometimes with long basal hairs, usually pilose elsewhere, occasionally glabrous or scabrous. Panicles with 5-15, evidently distinct branches in 1-2(3) whorls; branches 4.5-8 cm, spikelet-bearing to the base, with 11-15 spikelets per cm distally. Spikelets with 1 bisexual and 1 sterile floret. Lower glumes 0.7-1.6 mm; upper glumes 2-2.7 mm; lowest lemmas 2.8-3.3 mm long, 0.4-0.6 mm wide, lanceolate to elliptic, sides not conspicuously grooved, mostly glabrous, margins shortly ciliate distally, hairs less than 1 mm, apices awned, awns 6-13 mm; second florets 0.4-0.7 long, about 0.1 mm wide, borne on an equally long or longer rachilla segment, not or inconspicuously bilobed, awned, awns 3-5 mm. Caryopses 1.4-1.5 mm long, 0.3-0.4 mm wide, ellipsoidal. 2n = 40.

Chloris radiata is a weedy species of the eastern Caribbean, Central America, and northern South America. It may be native to Florida, but the record from Linton, Oregon, was from a ballast dump. The species is no longer found in Oregon.