No. 40. 
BOUTELOUA HUMBOLDTIANA Kunth. 
Culms erect, rarely branching, firm, 15 to 20 inches high, smooth, leafy below. 
Leaves: sheath open, striate, shorter than the internodes; ligule inconspic- 
uous; blade 1 to 2 lines wide, 3 to 6 inches long, scabrous especially on the mar- 
gins, often sparsely ciliate below. 
Inflorescence racemose, 3 to 4 inches long, consisting of about 7 to 9 one-sided, 
short- pedicelled spikes, lower ones 4 inch or more distant, others gradually shorter; 
spikes about 4 inch long, each consisting of 7 to 9 smooth spikelets, somewhat 
loosely overlapping each other. 
Spikelets about $ inch long, including the awns, smooth, consisting of 2 to 3 
flowers, upper male, others perfect, or the lower 2 fertile and the upper reduced 
to an awn. 
Empty glumes nearly equal, 3 to 4 lines long, keeled, lanceolate, acute; flower- 
ing glume of the lower flower 4 lines long, lanceolate, 3-nerved, 3-toothed, at the 
apex of the second flower similar, but with the teeth extended into long awns (2 
to 3 lines long). 
Palet nearly as long as the glume, 2-nerved, 2-toothed at the apex. Third 
flower when present, sometimes with awns still longer, or imperfect or reduced. 
PLATE XL: a, spikelet; b, empty glumes; c, flowering glume of the fertile 
flower; d, palet of the fertile flower; c’, flowering glume of the second flower; a’, 
palet of thesecond flower. The sterile flower reduced toa small pedicel is seen in a. 
It is doubtful whether this plant, which has passed under the name B. Hum- 
boldtiana, is really identical with that described by Kunth. Our plant is more 
probably a form of B. bromoides Lag. In range it seldom extends north of New 
Mexico, 
