GRASS FAMILY. 137 
12. Aristida desmantha Trin. & Rupr. 
Western Aristida. (Fig. 308. ) 
Aristida desmantha Trin. & Rupr. Mem. Acad. St- 
Petersb. (VI.) 5: 109. 1842. 
Culms 1°-2° tall, erect, branched, smooth and 
glabrous. Sheaths shorter than the internodes, 
smooth, glabrous or the lower sometimes pubes- 
cent ; ligule short ; leaves 6/-12/ long, less than 
1’’ wide, attenuate into a slender point, smooth 
beneath, scabrous above ; panicle about 6’ long, 
the branches slender, ascending; outer scales 
of the spikelet about equal, the third one 
shorter ; awns spreading or reflexed, somewhat 
coiled, united at base into a column less than 
1’ long, which is articulated to the scale. 
In dry soil, Kansas (?), the Indian Territory and 
Texas. Aug.-Sept. 
22. STIPA L,. Sp. Pl. 78. 1753. 
Generally tall grasses, the leaves usually convolute, rarely flat, the inflorescence panicu- 
late. Spikelets 1-flowered, narrow. Scales 3; the two outer narrow, acute or rarely bearing 
an awn, the third rigid, convolute, with a hairy callus at the base, and bearing a more or less 
bent awn, which is spiral at the base, and articulated tothescale. Palet 2-nerved. Stamens 
3, rarely fewer. Styles short, distinct Stigmas plumose. Grain narrow, free, tightly en- 
closed in the scale. [Greek, in allusion to the tow-like plumes of some species. ] 
A genus of about 100 species, distributed throughout the temperate and tropicalzones. Besides 
the following, some 20 others occur in the southern and western parts of North America. 
Outer scales of the spikelet 2'’-6'’ long: 
Obtuse or blunt-pointed, 2’’ in length. ay oS: 
Acute, 4/’-6'’ in length. 
Awn less than five times the length of the scale. 2. S. viridula. 
Awn more than seven times the length of the scale. 3. S. avenacea. 
Outer scales of the spikelet 10'’ long or more. 
Base of panicle usually included in the upper sheath; third scale 4'’-6'' long; awn slender, 
curled. 4. S. comata. 
Panicle exserted from the upper sheath; third scale 7'’-12'’ long, bent. 5. S. spartea. 
. Macount?. 
1. Stipa Macoutnii Scribn. Macoun’s Stipa. (Fig. 309.) 
Stipa Richardsonii A. Gray, Man. Ed. 2, 249. 
1856. Not Link, 1833. 
Stipa Macounti Scribn.; Macoun, Cat. Can. Pl. 5: 
390. 890. 
Culms glabrous, 1°—-2° tall, erect, simple, slen- 
der, smooth or somewhat scabrous. Sheaths 
shorter than the internodes; ligule about 1/ 
long, obtuse or truncate; leaves 2’-5’ long, 
4//-1/’ wide, flat, becoming involute-setaceous 
in drying, scabrous; panicle 2/-5’ long, con- 
tracted, the branches 1/-2’ long, erect, naked 
below; spikelets borne at the ends of the 
branches; outer scales about 2’ long, obtuse or 
blunt-pointed, glabrous; third scale somewhat 
shorter, pubescent with long appressed silky 
hairs, callus obtuse; awn 4//-5’’ long, contorted. 
New Brunswick tothe Northwest Territory, south 
to Maine, New Hampshire, Lake Superior and 
Montana. July. 
