1048 ANALYTICAL KEY 



m Panicle contracted; spikelets 4-5 mm. long, y-n-fld.; fl. glumes 



broad and rounded RHOMBOLYTRIUM. 



mm Panicle diffuse; spikelets 6mm. long, i-3-fld.; fl. gls. narrow, 



acute REDFIELDIA. 



// Ligule scale-like. 



m Fl. glume rounded; rachis glabrous; e.g. = spk SCOLOCHLOA. 



mm Fl. glume keeled. 



n Rachis hirsute; e.g.<spk GRAPHEPHORUM. 



n;i Rachis glabrous; e.g. = spk DUPONTIA. 



(See also Poa ) 

 ee Hairs or bristles at base of flowering glumes, if present, grading over into 



those on the flowering glumes. 

 / Spikelets in little clusters (of 2-5) of two very distinct sorts, one sterile of 



many glumes usually concealing the few-fld. fertile; e.g. < spk. 

 g Glumes of both kinds of spikelets obtuse; fertile spikelets i-fld. 



(LAMARCKIA.) 



gg Glumes of the very flat sterile spikelets pointed or awned; fertile 2-3-fld. 



CYNOSURUS. 



jff Spikelets not conspicuously dimorphic; or if so then the fertile and sterile 

 not in the same little clusters, or the sterile with few glumes (4 or less) 

 or rudimentary. 

 g Blade articulated with the sheath and eventually deciduous at this point; 



branched plants with large lanceolate leaves; e.g. < spk. 

 h Internodes not flattened; sheaths persistent. 



i Stamens 3; empty glumes 2, short ARUNDINARIA. 



ii Stamens 6; empty glumes 2-6, gradually increasing in size upward. 



(BAM BUS A.) 



hh Internodes flattened at least on one side; sheaths soon deciduous; 

 stamens 3; the 1-2 spikelets surrounded by a large leaf at the 



base (PHYLLOSTACHYS.) 



gg Leaves not articulated with the sheath, though sometimes with a dif- 

 ferent-colored zone at this point. 



h Flower-bearing glumes rugose with transverse and longitudinal cellular 

 reticulations; palet similar, i -nerved; two much shorter empty glumes, 



and still two more fold-like ones at the base (ORYZA.) 



hh Flower-bearing glumes and spikelets not as above. 

 i Empty glumes at base of spikelet strongly transversely wrinkled or 

 pitted, thick and coriaceous; spikelets imbedded in the thickened 



rachis and very closely appressed; e.g. = spk MANISURUS. 



ii Empty glumes at base of spikelet not strongly transversely wrinkled 



nor pitted as above. 

 j Rachis of spike-like inf. very thick ; pist. spikelets at its base and imbedded 



in it; stam. spikelets above, not imbedded; e.g. = spk TRIPSACUM. 



jj Rachis slender and spikelets often paniculate. 



k Spikelets in pairs at each node of the spike-like branches of the in- 

 florescence, one longer pediceled than the other; fl. gl. and rachis 

 with long silky spreading hairs; e. gls. three; fl. gl. awned; e.g.= 



spk .' ERIANTHUS. 



kk Spikelets 2-3 at each node of the simple spike-like inf., 5 mm. or 



more long. (See also kkk.) 

 I Empty glumes at base of spikelet absent or minute and awn-like; 



spike very open with spreading long-awned spikelets HYSTRIX. 



// Empty glumes present; spikelets usually ascending and approximate; 



e.g.= or <spk. 



m Spikelets i-fld., or with a mere rudiment of a second; lateral spike- 

 lets usually imperfect HORDEUM. 



mm Spikelets, at least most of them, 2- or more-fld., all usually similar. 

 n Rachis of spike easily breaking up at maturity; western . SITANION. 



nn Rachis not breaking up into joints ELYMUS. 



kkk Spikelets solitary at each joint of the spike, or panicled. 



