IO48 ANALYTICAL KEY 



m Panicle contracted; spikelets 4-5 mm. long, 7-11-fld.; fl. glumes 



broad and rounded Rhombolytrium. 



mm Panicle diffuse; spikelets 6 mm. long, 1-3-fld.; fl. gls. narrow, 



acute Redfieldia. 



II Ligule scale-like. 



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



mm Fl. glume keeled. 



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



nn 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. 

 J 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. 



Cynosurtjs. 

 Jf 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 rudimentarv. 

 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. 



(Bambusa.) 



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 (Phyllostach ys.) 



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 Hystrtx. 



// 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-fid., all usually similar^ 

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



nn Rachis not breaking up into joints Elymus.' 



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





