Hitchcock — Tlic Grasses of Hawaii 107 



KEYS. 



KEY TO THE TRIBES. 



Subfamily Poatae. Spikelets i to man\-flo\vere(l. the reduced florets, if any. above the perfect 

 florets (except in Phalarideae ) : articulation usually alxive the glumes : spikelets usually 

 more or less laterally compressed. 



Plants woody, the culms perennial: spikelets several-flowered BAMBOSEAE. 



Plants herbaceous, the culms annual. 



Spikelets with 2 staminate, neuter, or rudimentary lemmas unlike and below the fertile 



lemma; no sterile or rudimentary florets above PHALARIDEAE. 



Spikelets without sterile lemmas below the perfect floret. 

 Spikelets sessile on a usually continuous rachis. 



Spikelets on opposite sides of the rachis: spike terminal, single HORDEAE. 



Spikelets on one side of the rachis: spikes usuallv more than i. digitate or 



racemose .' CHLORIDE AE. 



Spikelets pedicellate in open or contracted, sometimes spikelike, panicles. 



Spikelets i-flowered AGROSTIDEAE. 



Spikelets 2- to many-flowered. 



Glumes as long as the lowest floret, usually as long as the spikelet : lemmas 

 awned from the back (spikelets sometimes awnless in Trisetum ) 

 AVENEAE. 



Glumes shorter than the first floret : lemmas awnless or awned from the 



tip or from a bifid apex FESTUCEAE. 



Subfamily 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 ( perfect in Isachne and Dissochondrus ) . commonly represented by a sterile 

 lemma only, one glume sometimes 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, or at least the 

 fruits, more or less dorsally compressed. 

 Glumes membranaceous, the sterile lemma like the glumes in texture ; fertile lemma and 



palea indurate or at least firmer than the glumes PANICEAE. 



Glumes indurate : fertile lemma and palea hyaline or membranaceous, the sterile lemma like 

 the fertile one in texture. 

 Spikelets unisexual, the pistillate below, the staminate above, on the same inflorescence; 



the pistillate (in our species) enclosed in a bony ovoid involucre or head 



TRIPSACEAE. 



Spikelets in pairs, one sessile and perfect, the other pedicellate and usually staminate 

 or neuter (perfect in Ischaemum) ANDROPOGONEAE. 



KEY TO THE GENERA. 



BAMBOSEAE. 



.\ single genus in the Hawaiian Islands I. Schizostaciivum (p. iio) 



FESTUCEAE. 



I^emmas 3-nerved 7. Er.\grostis (p. 123) 



Lemmas 5 to many-nerved. 



Lemmas as broad as long, the margins outspread: florets closely imbricate, horizontall) 

 spreading 6. Briz.\ (p. 123) 



[9] 



