PIPER FLORA OF THE STATE OF WASHINGTON. 103 



Lemma awaless or short-awned, and loosely envelopino; the giaiti. 

 Inflorescence a dense spike. 



Spikelets early deciduous: lemma with a dorsal awn. .. Ai.opecurus (p. 110). 

 Spikelcts persistent ; lemma awnless or with a terminal 

 awn. 



Spikes ovoid; glumes long-awned Polypogox (p. 111). 



Spikes cylindric; glumes not long-awned Phleum (p. 111). 



Inflorescence a loose panicle. 



Fruit a utricle Sporobolus (p. 112), 



Fruit a grain. 



Palet 1-nerved; stamen 1 Cinna (p. 113). 



Palet 2-nerved ; stamens 3. 



Glumes none; plant, minute Coleanthus (p. 114). 



Glumes 2. 



Callus with a tuft of long hairs at liase. . . Oalamagrostis (p. 114). 

 Callus naked Agrostis (p. 118). 



AYENEAE. 



Perfect flower only one, the other staminate. 



Lower flower perfect; upper staminate and awned Holcus (p. 121), 



Lower flower staminate, long-awned; second flower perfect, 



awnless Arrhenatherum (p. 121). 



Perfect flowers 2 or more. 



Rachilla not prolonged beyond the upper flower Aira (p. 121). 



Rachilla prolonged beyond the upper flower. 



Awn of the lemma arising between the two terminal 



teeth Merathrepta (p. 122). 



Awn of the lemma dorsal. 



Florets large, more than 1.5 mm. long Avena (p. 123). 



Florets small, less than 1.5 mm. long. 



Lemma erose-truncate Deschampsia (p. 123). 



Lemma 2-toothed Trisetum (p. 124). 



FESTUCEAE. 



Lemma 3-nerved, rarely 1-nerved. 



Rachilla with long hairs Phragmites (p. 125). 



Rachilla glabrous or with short hairs. 



Glumes obtu.se, very unlike, the upper inclosing the 



flowers Estonia (p. 125). 



Glumes subequal, acute. 



Panicle close; .spikelets 2 to 4-flowered Koeleria (p. 126). 



Panicle loose; spikelets usually many-flowered Eragrostis (p. 126). 



Lemma 5-nerved or more. 



Spikelets with the upper florets sterile and folded about each 



other Melica (p. 127). 



Spikelets with the upper florets perfect, or narrow and abor- 

 tive. 



Keels of the palea winged Pleuropogon ( p. 128). 



Keels of the palea not winged. 



Stigmas arising below the apex of the ovary Bromus (p. 141). 



Stigmas arising at the apex of the ovary. 

 Lemmas compressed and keeled. 



