No. 26. 
MUHLENBERGIA GRACILIS Trinius. 
Rootstocks short, ascending. 
‘ul peed: erect, 9 to 24 inches high, seen eas above the base, glabrous. 
Leaves all radical; sheaths of the outer ones short (1 to 3 inches long), loose, 
dattatied, ‘slightly scabrous on es back, inner longer and sheathing, uppermost 
usually reaching to, and sheathing, the inflorescence; blade 6 inches or less long, in 
line with the sheaths, usually agi scabrous on the back, glabrous above; 
ligule membranaceous, about $ to $ inch long, at the base broader than the blade, 
apex slender-acute and often lacerate, the whole shriveled when old. 
Inflorescence paniculate. Panicle sheathed or long-pedunculate, 2 to 7 inches 
long, erect or nearly so; rachis scabrous; branches scabrous, 2 inches long or less, 
nearly erect. 
Spikelets lanceolate, acute, 2 lines long exclusive of the awn, borne singly on 
short pedicels. 
umes 3; first lanceolate, acuminate-aristate, 1-nerved, scabrous on the back, 
about 1 line long, lead-colored below, hyaline above; second slightly longer, sim- 
ilar in texture, scabrous on the back, ovate-oblong, keunwais: 3-nerved, nerves pro- 
duced into aristate points; third (flowering) lanceolate, involute, 1-nerved or with 
two additional nearly marginal nerves, scabrous on the back, ciliate on the mar- 
gins, as long as the spikelets, straw-colored, with a SNe aot apex tapering into 
a not twisted slender, scabrous, flexuous awn about $ in 
Flower single, hermaphrodite. Palet lanceolate, aod shorter than its 
glume, obtuse when flattened, 2-nerved, scabrous on the back. Stamens 3; an- 
thers linear, about 1 line long. Stigmas cylindrical, purple. 
Grain not seen. Palet and glume coriaceous when old. 
PLATE XXVI; a@ and Bb, spikelet, the parts spread open, and the rachilla 
broken above the second glume; ¢, second glume; a, first acre é, same as 
showing the back of the dieutae glume. 
This species is common on sed ridges or hills from Mexico to Montana, and 
a small form occurs in Califo 
