112 Key to the System of 



Hilum of more than half the length of the fruit. 



Fruit -supporting bract dorsally convex, pointed or awned ; 

 stamens three, rarely two or one ; styles terminal ; fruit 

 unbearded. Pestuca. 2095 



551. Spikelets unilaterally arranged in unitedly terminal 



or rarely dispersed spikes. 



Spikelets jointed only above the outer bracts ; all bracts 

 awnless, but often pointed ; fruit-supporting bract pro- 

 minently keeled ; stamens three. Eleusiiie. 2097 



Spikelets arranged in a solitary spike or cluster or 

 panicle ... ... 552 



552. Fruit soon dropping from its bracts. 



Spikelets usually arranged in a panicle, between the flowers 

 imperfectly jointed ; flowers much compressed ; fruit- 

 supporting bract membranous, lobeless, lined with three 

 venules, the middle venule somewhat carinal ; covering 

 bract persistent ; stamens three or two. Eragrostis. 2098 



Fruit free, but retained by its bracts ... ... 553 



553. Spikelets awnless ... ... ... ... ... 554 



Spikelets awned ... ... ... ... 555 



554. Fruit-supporting bracts lobeless or slightly notched at 



the summit. 



Spikelets generally arranged in a panicle ; flowers much 

 compressed, often beset with hairlets at the base, seldom 

 numerous in their spikelet ; fruit-supporting bracts lined 

 by five venules ; stamens three ; hilum much shorter than 

 the fruit. Poa. 2104 



Fruit-supporting bracts three-lobed at the summit. 



Spikelets generally arranged in a panicle ; fruit-supporting 

 bracts rigid, dorsally convex, lined by three venules ; 

 stamens three. Triodia. 2112 



555. Fruit-supporting bracts three-awned. 



Spikelets arranged in a contracted or somewhat spreading 

 panicle; rhacheole jointed bet ween all the flowers; stamens 

 three. Triraphis. 2113 



Fruit-supporting bracts one-awned ... ... ... 556 



