GRASS FAMILY. 133 
at. ARISTIDA L,. Sp. Pl. 82. 1753. 
Grasses varying greatly in habit and inflorescence. Leaves narrow, often involute-seta- 
ceous. Spikelets narrow, 1-flowered. Scales 3, narrow, the two outer carinate ; the third 
ridged and conyolute, bearing three awns occasionally united at the base, the lateral awns 
rarely wanting or reduced to rudiments. Palet 2-nerved. Stamens 3. Styles distinct. 
Stigmas plumose. Grain free, tightly enclosed in the scale. [Latin, from av/s/a, an awn. | 
About roo species, in the warmer regions of both hemispheres. Besides the following, some 
20 others occur in the southern and western parts of North America. The English name 7hree- 
awned Grass is applied to all the species. 
Awns not articulated to the scale nor united at the base. 
Lateral awns usually erect, not more than half as long as the horizontal or reflexed, central 
one, generally much shorter or occasionally wanting. 
Third scale, exclusive of awns, 3'’ long or less. 
Central awn spiral at base, terminal straight portion 2''—3'' long. . A. dichotoma. 
Central awn not spiral at base, terminal straight portion a ~7'' long. fk A. gracilis. 
Third scale, exclusive of awns, 4'’ long or more. 
Central awn spiral, lateral awns one-quarter to one-half as long. 3. A. bastramea. 
Central awn not spiral or rarely so, reflexed, lateral awns less than one-sixth as long or 
wanting. 4. A. ramosissima. 
Lateral awns usually diverging, more than half as long as the horizontal or divergent central 
one, generally about equalling it. 
First scale exceeding the second. 
Sheaths glabrous. 5. A. purpurascens. 
Sheaths, at least the lower ones, woolly. 6. A. lanata. 
First scale half as long as the second or equalling it. 
First seale 5-nerved, or occasionally 7-nerved at base. 7. A. oligantha. 
First scale 1-nerv' ed, sometimes with an obscure additional nerve on each side, 
Central awn I 3g) -4! long; panicle 4’-6' long, lax, few-flowered. 8. A. purpurea. 
Central awn 1’ long or Tess. 
Culms simple; panicle strict, 6’-2° long. g. A. stricta. 
Culms branched; panicle somewhat lax, not 1° long. 10. A. dispersa. 
Awns articulated to the scale, more or less united at the base. 
Column of the awns conspicuous, 3'’ long or more. 
Column of the awns inconspicuous, less than 1’’ long. 
1. Aristida dichotoma Michx. Poverty 
Grass. (Fig. 297.) 
Aristida dichotoma Michx. Fl. Bor. Am. 1: 41. 1803. 
Aristida dichotoma var. Curtissii A. Gray, Man. Ed. 6, 
640. 1890. 
Culms 6/—-2° tall, erect, slender, dichotomously 
branched, smooth or roughened. Sheaths much 
shorter than the internodes, loose, smooth and glab- 
rous; ligule very short, ciliate; leaves 1/—3/ long, less 
than 1’ wide, involute, acuminate, usually scabrous; 
spike-like racemes or panicles 2/-5’ long, slender; 
spikelets about 3’’ long ; outer scales nearly equal or 
the lower somewhat shorter, usually awn-pointed ; 
third scale shorter than the second, the middle awn 
horizontal, coiled at base, the terminal straight por- 
tion 2’’-3’’ long, the lateral awns 1’’ long or less, erect. 
_Dry sandy soil, Maine to Ontario, Missouri and the In- 
dian Territory, south to Georgia and Texas. Aug.—Sept. 
. tuberculosa. 
. desmantha. 
2. Aristida gracilis Ell. Slender Aristida. 
(Fig. ree 
Aristida gracilis El. Bot. S. C. & Ga. 1: 142. 1817. 
Aristida ‘gracilis var. peas oa A. Gray, Man. Ed. 
5, 618. 1867. 
Glabrous and smooth throughout, culms 6/2 
tall, erect, simple or branched. Sheaths shorter 
than the internodes ; ligule very short ; leaves 1/— 
4’ long, 1’’ wide or less, flat, or involute when dry ; 
panicle spike-like, 3/-7’ long, slender; spikelets 
about 3/’ long; outer scales equal, or the lower 
somewhat shorter, awn-pointed ; third scale about 
equalling the second, generally mottled, middle 
awn horizontal, the terminal straight portion 3/’— 
7’’ in length, the lateral awns 1//-3/ long, erect. 
Dry soil, Massachusetts to Illinois and Nebraska, 
south to Florida and Texas. Aug.—Sept. 
° 
