PIPER FLORA OF THS: STATE OF WASHINGTON. 103 



Lemma awnless orshort-awned, and loosely enveloping the grain. 

 Inflorescence a dense spike. 



Spikelets early deciduous; lemma with a dorsal awn Alopecurus (p. 110). 



Spikelets persistent; lemma awnless or with a terminal 

 awn. 



Spikes ovoid; glumes long-awned Polypogon (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 base Calamagrostis (p. 114). 



Callus naked Agrostis (p. 118). 



AVENEAE. 



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 Merathrbpta (p. 122). 



Awn of the lemma dorsal. 



Florets large, more than 15 mm. long Avena (p. 123). 



Florets small, less than 15 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 obtuse, 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. 



