No. 2, 
ARISTIDA ARIZONICA Vasey. 
Rootstocks unknown. Roots rather stout, simple above, with a thin bark. 
Culms erect, simple, closely tufted, 1 to 24 feet high, glabrous. 
Leaves all radical or originating néar the base of the culm; sheaths imbricated, 
glabrous, sometimes 6 inches long; blades commonly 3 to 5, sometimes 10 inches 
long, glabrous, involute when dry ; ligules a minute dense ring of hairs. 
Inflorescence an exsert-pedunculate panicle 4 to 12 inches long; branches short, 
rarely exceeding 2 inches, nearly erect; spikelets singly sessile or short pedunculate. 
Spikelets (excluding the awns) 4 to ? inch long, awl-shaped, nearly terete. 
Glumes 3; first linear, two-thirds the length of the spikelet, membranaceous, 
l-nerved, aristate, acute with 2 minute accessory teeth, the midnerve and awn- 
point scabrous ; second as long as the spikelet, narrower than the first, similar to it, 
the awn-point a little longer; third (flowering) glume coriaceous, as long as the 
second, closely involute, very slender, scabrous ; apex twisted twoor three times, 
then produced into 3, straight, terete, not twisted, scabrous awns diverging when 
dry, usually a little longer than the spikelet ; middle one slightly the longest ; 
rachilla slightly elongated between the second and third glumes, densely villous. 
Flower single, hermaphrodite. Palet minute, nearly 1 linelong. Lodicules 2, 
lanceolate, as long as the palet. Stamens 3, anthers linear nearly 1 line long. 
Stigmas 2, cylindrical. 
Grain awl-shaped, about 4 lines jong, closely enwrapped in . the flowering glume; 
rachilla disarticulating obliquely just above the second glume. 
PLaTE XXII; a, spikelet, empty glumes spread open; 0b, the same empty 
glumes en. flowering glume open to show the palet and stamens. aoe 
stigmas are not shown. 
A common grass of the mesas and hills, which early in the season furnishes 
good grazing for animals. 
