266 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM, 
Inflorescence not a dense golden brown silky panicle; pedicellate spike- 
let staminate or rudimentary. 
Pedicel of the sterile spikelet thickened, appressed to the thickened 
rachis joint, or adnate to it. 
Sessile spikelets sunken in cavities of the thickened rachis, the 
first glume covering the opening; sterile spikelet obscure. 
8. Manisuris (p. 275). 
Sessile spikelet not sunken in the rachis, the adnate rachis 
joint and pedicel sunken in the opening of the globose 
first glume; sterile spikelet large___9. Rytilix (p. 276). 
Pedicel of the sterile spikelet distinct, this and the rachis joint 
usually slender, 
Spikelets in reduced racemes of 1 to 5 (rarely 7) joints, these 
peduncled in open panicles; awns, if present, commonly 
deciduous. 
Pedicellate spikelets staminate______ 15. Holcus (p. 286). 
Pedicellate spikelets wanting, the pedicel only present. 
16. Sorghastrum (p. 286). 
Spikelets in evident racemes of several to many joints. 
Blades cordate, thin; pedicellate spikelets obsolete or pres- 
ent only in the lower part of the delicate subdigitate 
racemes___ 11. Arthraxon (p. 277). 
Blades linear, not cordate; pedicellate spikelets present, at 
least as rudiments. 
Inflorescence an elongate panicle of whorled long- 
peduncled slender glabrous racemes; spikelets muri- 
cate, awnless____________ 14. Anatherum (p. 285). 
Inflorescence not a panicle of long-peduncled racemes ; 
spikelets not muricate; racemes commonly conspicu- 
ously woolly. 
Racemes 2, forking from the summit of the slender 
peduncle, a staminate awnless spikelet borne in 
the fork ____.-_______ 13. Cymbopogon (p., 284). 
Racemes 1 to many, not ferking with a spikelet borne 
in the fork____________ 12. Andropogon (p. 277). 
3. NAZIEAE. 
Spikelets solitary, finally reflexed; glumes subulate, awnless. 
22. Leptothrium (p, 289). 
Spikelets 2 or more in a cluster, falling together. 
Glumes smooth, connate at base, forming a pitcher-shaped false involucre, 
20. Anthephora (p. 288), 
Glumes covered with hooked spines, forming little burs, not connate. 
21. Nazia (p. 289). 
4, MELINIDEAE, 
Spikelets awnless ; inflorescence an attenuate panicle____24. Triscenia (p. 290). 
Spikelets awned ; inflorescence a many-flowered panicle. 
Glumes awnless, the lemma with a bent or twisted awn. 
23. Arundinella (p. 289), 
Glumes awned, the awns straight; lemma awnless__25. Achlaena (p. 290). 
