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conical floret, nearly equal, l-nerved, membranaceous, often purple, 
acute, bristle pointed or obtuse and denticulate; floral glume slightly 
thicker, rolled about the palet and grain, 3-nerved, lateral nerves often 
obscure, more or less pubescent near the base, mucronate or awned 
from between the two inconspicuous teeth at the apex; palet thin, 
equaling the glume, pubescent on the two nerves near the base: callus 
at the base of the floret inconspicuous, shortly pubescent or obsolete: 
grain terete or oblong, transluscent, amber-colored.—Mostly perennial, 
various in habit. 
§1. Panicle very open, diffusely spreading; branches and pedicels capillary.—TRICHO- 
CHLOA. 
* Culms erect, simple above the strongly rooted base, or branching matted rootstocks. 
+ Culms 5 to 10dm. high: leaves 1 to 3 dm. long; ligules prominent, nearly Z em. long. 
1. M. capillaris (Lam.) Trin. (MUHLENBERG’S HAIR-GRASS,) Culms 6 to 10 dm, 
high, smooth: leaves 2 to 4 dm, long, narrow becoming involute, scabrous or nearly 
smooth: panicle 2 to 5dm. long: spikelets 4 to 5mm. long, minutely scabrous; 
empty glumes subequal, bristle-pointed, one half as long as the floret; callus small, 
with short hairs; awn about lem, long (Stipa capillaris Lam.)—Dry sandy land, 
central Texas to Florida and Virginia, Var, rRICHOPODEs (Ell.) Vasey, of the same 
range, has empty glumes generally smaller and not awn-pointed, and awn of floral 
glume about as long as the floret. (Agrostis trichopodes Ell.) 
2. M. affinis Trin. Culms 4 to 8 dim. high, smooth: leaves mostly involute, 2 to 4 
dm. long; sheaths retrorsely roughened, exceeding the internodes: panicle 1 to 3dm. 
long, purple; branches and long pedicels finely capillary, erect spreading: spikelets 
4mm. long, minutely scabrous; empty glumes obtuse, erose or denticulate, sub- 
equal, one-fourth as long as the floret; awn nearly 2cm. long; hairy callus small.— 
Low land, western Texas to Arizona. 
3. M. Reverchoni Vasey. Culms 3 to 6dm. high, slender, smooth: leaves mostly 
flat except the involute points, smooth except the slightly hispid upper surface, 8 to 
12cm. long: panicle pyramidal, | to 2 dm. long: spikelets 4 to 5 mm. long; empty 
glumes nearly equal, acute or the second acuminate and bristle-pointed, about one- 
third as long as the floret; awn slightly shorter than the tloret,—Hillsides, western 
Texas. 
+ + Culms 8 to ddm. high: leaves 1 dm. long ox less. 
++ Ligule fimbriate, less than Imm, long. 
4. M. pungens Thurb. Culms 3 to 5dm, high, hoary or puberulent: leaves 
rigidly divergent, involute, pungently pointed, 5cm. long: panicle 1 to 2dm. long, 
pyramidal: branches 4 to 6, single, bearing long branching subdivisions from near 
the base: spikelets 3 to 4 mim. long; empty glumes subequal, acute, usually with 
two lateral teeth, one-half as long as the floret; floral glume acute or merely bristle- 
pointed; palet with two bristle points; the small callus almost glabrous.—Sand 
hills, western Texas to Nebraska and Arizona, 
++ 4+ Ligule 3 to 5 mm. long. 
5. M. arenicola Buckl. Culms 3 to 6 dm, high, slender, inclosed to the panicle 
in the long sheaths: leaves erect, narrow, mostly involute: panicle one-half as long 
as the culm, pyramidal; branches alternate or subverticillate, naked near the base: 
spikelets 3 mm. long, somewhat appressed on rather short pedicels; empty glumes 
acute, one-half to two-thirds as long as the short-awned floret; floral glume 
minutely pubescent near the base.—Mesas and foothills, western Texas to Arizona. 
