H TRIANDRIA.— DIGYNIA. 



floret antheriferous : inferior valve 2-cleft, awned 

 below the middle. Superior floret perfect ; inferior 

 valve cleft, unarmed, or with a short awn a little 

 below the tip. 



83. AVENA. Cal. membranaceous, many-flowered, 



generally longer than the florets. Cor. mostly 

 bearded at the base : inferior valve bilaciniate, with 

 a twisted awn on the back. Seed coated. 



84. AIRA. Cal. 2 — 3-flowered, longer than the florets. 



Inferior valve of the Cor. eroded or many-toothed, 

 awned on the back below the middle. 



b. Flowers spiked. 



1. Calyx l-valved. 



35. LOLIUM. Spikelets sessile on a rachis, many-flow- 

 ered. Calyx of 1 glume. Inferior valve of the 

 cor. herbaceo-membranaceous, mucronate, or with 

 a short bristle at the tip. 



2. Calyx 2-valved. 



SG. ELEUSINE. Spikes digitate, unilateral. Cal. mem- 

 branaceous^ — 6-flowered ; glumes obtuse,unequal. 

 Cor. membranaceous, unequal, unarmed ; inferior 

 valve carinate, the superior concave on the back. 

 Seed triangular, transversely rugose. 



87. TRITICUM. Spikelets sessile on the teeth of the 

 rachis, 3 — 4-ftowered ; the 2 inferior florets oppo- 

 site, fertile ; the upper ones often abortive. Glum. 

 broad, boat-shaped, mucronate or armed. Inferior 

 valve of the cor. terminating in a bristle ; superior 

 valve subconcluplicate. 



38. AGROPYRON. Spikelets sessile on the teeth of 



the rachis, 3 — 9-flowered. Glum, lanceolate, 

 carinate. Inferior valve of the cor. mucronate, or 

 terminating in a subulate bristle. 



39. SECALE. Spikelets sessile on the teeth of the 



rachis, 2 — 3-flowered ; the terminal floret abortive. 

 Cal. 2-valved ; glumes subulate, opposite, shorter 

 than the florets. Inferior valve of the Cor. terminat- 

 ing in a long bristle. 

 30. ELYMUS. Spikelets 2 or more at each joint of the 

 rachis^ — 9-flowered. Cr/ttm.(involacruHa) geminate. 



