56 



GRAMINACEAE 



AGROSTIDEAE — RESDTOP TRIBE 



1. Spikelets in a cylindrical spike 



a. Lemma without an awn ; glumes awn-pointed or aristate 



b. Lemma awned ; glumes not aristate 



2. Spikelets in a panicle or spike-like panicle 



a. Spikelets in a dense spike-like panicle 



b. Spikelets in an open panicle 



(1) Lemma firm and hard at maturity, closely enveloping the grain 



(2) Lemma thin or membranous at maturity, glumes coarse, grain loose 

 x. Lemma with a tuft of straight hairs at its base 



(x) Rachilla prolonged behind the palet, bristle-like 

 (y) Rachilla not prolonged behind the palet 

 y. Lemma without a tuft of hairs at its base 



(x) Glumes longer than, and inclosing, the lemma 

 (y) Glumes shorter than, and not inclosing, the lemma 

 m. Stems wiry or rigid ; lemma and palet not raised on a short 



pedicel 

 n. Stems not wiry ; lemma and palet raised on a short pedicel 



Phleum — Timothy 



(Gr. phleos, a kind of reed) 

 A single cultivated species 



Alopecurus — Foxtail Grass 



(Gr. alopex, fox, oura, tail, referring to the spike) 

 A single species 



Muhlenbergia — Muhlenbergia 



(Named for Muhlenberg, an American botanist of the fSth 



1. Glumes equalling the lemma 



2. Glumes much longer than the lemma 



Orvzopsis — Mountain Rice 



(Gr. oryza, rice, opsis, likeness; of little meaning) 

 A single species (at this season) 



A single species 

 A single species 



Calamagrostis — Blue joint Grass 



(Gr. kalamos, reed, agrostis, grass) 



Calamovilfa — Reed Grass 



(A hybrid name of doubtful meaning) 



Agrostis — Red Top 



Phleum 

 Alopecurus 



Muhlenbergia 



Oryzopsis 



Calamagrostis 

 Calamovilfa 



Agrostis 



Sporobolus 

 Cinna 



P. prate use 



A. geniculdius 



century) 

 .1/. mexicdna 

 M. racemosa 



O. melanocdrpa 



C. canadensis 



C. longijolia 



(Gr. agros, field, from its home) 



1. Palet at least one-half as long as the lemma, 2-nerved A. alba 



2. Palet minute and nerveless or wanting A. hiemdlis 



Sporobolus — Rush-grass, Drop-seed 



(Gr. spora, seed, bolps, throwing) 



1. Slender plants, the spike-like panicle exserted beyond the upper leaf 



sheath 



2. Coarse wiry plant, the much branched panicle more or less inclosed by 



the upper leaf sheath 



Cinna — Wood Reed-grass 



(Gr. kinna, a kind of grass) 



A single species 

 A single genus 



AVENEAE — OAT TRIBE 



S. cuspi'ldtus 

 S. cryptdndrus 



C. arundinacea 



Arena 



