GRASS FAMILY 
191 
Spikelets on one side of the rachis; spikes usually more than 1, digitate 
or racemose.— Chlorideae (Grama Tribe). 
Spikes digitate ; rachilla a'rticulate above the glumes. ...25. Cynodon. 
Spikes racemose, erect or nearly so ; rachilla articulate below the 
glumes, the spikelets falling entire. 26. Spartina. 
Spikelets with 2 staminate, neuter, or rudimentary lemmas unlike and below the 
fertile lemma; no sterile or rudimentary florets above.— Phalarideae 
(Canary Grass Tribe)...i.27. Phalaris. 
Subfamily 2. Panicatae 
Spikelets with one perfect terminal floret (disregarding those of the 
few monoecious genera and the staminate and neuter spikelets) and a 
sterile or staminate floret below, usually represented by a sterile lemma 
only, one glume sometimes (rarely both glumes) wanting; articulation 
below the spikelets, either in the pedicel, in the rachis, or at the base of 
a cluster of spikelets, the spikelets falling entire, singly, in groups, or 
together with joints of the rachis. 
Spikelets strongly laterally compressed; stamens 6.—Tribe Oryzeae (Rice Tribe) 
28. Oryza. 
Spikelets more or less dorsally compressed ; stamens 3. 
Spikelets all alike ; glumes and sterile lemma membranaceous, fertile lemma 
and palea indurate.— Paniceae (Millet Tribe). 
Spikelets pedicellate in open panicles; no ring-like callus at base of 
the spikelet. 29. Panicum. 
Spikelets subsessile in slender racemes; racemes paired or racemose; 
first glume and the rachilla-joint forming a swollen ring-like 
callus at the base of the spikelet.30. Echinochloa. 
Spikelets in pairs, one sessile and perfect, the other pedicellate and staminate 
or neuter (the pedicellate one sometimes obsolete, rarely both pedi¬ 
cellate) ; glumes firm, lemmas hyaline.— Andropogoneae (Sorghum 
Tribe). 
Inflorescences of one kind : flowers polygamous, in panicles....31. Holcus. 
Inflorescences unisexual, of two kinds, the staminate flowers in a ter¬ 
minal panicle, the pistillate flowers in a spike, borne in the leaf 
axils ...—.32. Zea. 
1. BROMUS L. Brome Grass 
Plants with closed sheaths, flat blades, and open or contracted panicles 
of large spikelets. Spikelets several to many-flowered. Glumes unequal, 
acute, the first 1 to 3-nerved, the second usually 3 to 5-nerved. Lemmas 
convex or keeled, 5 to 9-nerved, 2-toothed at the apex, awnless or usually 
awned from between the teeth. Palea usually shorter than the lemma. 
( Ancient Greek name for the oat.) * 
Plants annual; introduced weeds. 
Lemmas narrow, gradually acuminate, the awn as long as the body of the 
lemma or longer. 
Panicle drooping; pedicels capillary...1. B. tectorum. 
Panicle erect; pedicels stiff. 
Panicle compact; pedicels mostly less than 5 mm. long; culms pubes¬ 
cent at summit.2. B. rubens. 
Panicle relatively loose, some of the pedicels at least 10 mm. long ; 
culms glabrous.3. B. madntensis. 
Lemmas broad, abruptly narrowed above, the awn mostly shorter than the 
body.-... 4 - B • rtgidus. 
Panicle contracted, usually dense, erect or nearly so : lemmas pubescent, 
sheaths velvety...5. B. hordeaceus. 
Panicle loose, nodding or drooping. 
