836 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM, 
Awns much shorter than the body 
of the lemma, but slightly 
exceeding the spikelet. 
Base of plant strong, woody, 
rhizomatous; fertile 
floret glabrous at base.. 16. 
Base of plant not woody nor 
rhizomatous; fertile 
floret pilose at base.... 15. 
Spikelets not pectinately arranged. 
Spikes many, usually 30 or more. 
Awns longer than the body of the spikelet; 
plants usually straggling. 
Spikes with a single spikelet; fertile 
lemma entire................-. 21. 
Spikes normally with 5 or more spike- 
lets; fertile lemma 3-toothed... 22. 
Awns much shorter than the body of the 
spikelet. 
Sheaths densely hairy; lower spikes 
compound........-..------.---- 20. 
Sheaths glabrous. 
Second glume about as long as the 
fertile floret. ............. 19. 
Second glume about half as long 
as the fertile floret........ 18. 
Spikes rarely as many as 20, usually fewer 
than 15. 
Glumes densely pubescent. 
Spikes 4 to 6, rhomboid in outline; 
sterile floret 1, deeply trifid, the 
middle awn flattened.......... 24, 
Spikes 10 to 20, triangular in outline; 
sterile florets 2, awned, the 
awns similar.......... . 25, 
Glumes glabrous or minutely pubescent on 
the nerves only. 
Spikelets few, crowded, the first floret 
fertile... 20.22. eee eee 23. 
Spikelets numerous, not crowded, the 
first floret mostly staminate, the 
second fertile. 
Plants smooth, grayish; culms 
geniculate. .............. 28. 
Plants more or less prominently 
papillose-pubescent. 
Base of plants hard, rhizo- 
matous; culms simple; 
spikes 2 to3 cm. long.. 27. 
Base of plants not rhizo- 
matous; culms branch- 
ing; spikes usually 
about 15 mm., some- 
times 20 mm. long.... 26 
B. karwinskii. 
B. rothrocki. 
B. juneea, 
B. disticha. 
B. pringlet. 
B. curtipendula. 
B. acuminata. 
B. chondrosioides. 
B. eludens. 
B. texana. 
B. repens. 
B. radicosa. 
_ B. filiformis. 
