56 POACEAE. 



scabrous, about 2 mm. broad; stem leaves 2; ligules well developed; sheaths 

 loose, becoming scarious; panicles green or purple, erect, rather loose, 4-7 cm. 

 long, the rays mostly in twos; spikelets lanceolate, 6-9 mm. long, loosely 3-5- 

 flowered; glumes subacute, smooth, subequal, about 4 mm. long; lemma ob- 

 scurely 5-nerved, oblong, subacute, scabrous on the back, puberulent at base 

 and on the keel, 4-4.5 mm. long. 

 Rocky places at high altitudes. 



Poa gracillima Vasey. Very similar to P. saxatilis which may not be 

 distinct; leaf blades involute; panicle loose; spikelets 7 mm. long; lemma thin, 

 scabrous on the back, pubescent at base, scarious at apex. 



On cliffs in the mountains. 



81. DISTICHLIS. 



Rather rigid erect grasses springing from creeping bases, 

 with dense panicles of rather few large and compressed spikelets, 

 which are usually more numerous and less crowded in the stami- 

 nate than in the pistillate plants; spikelets 8-16-flowered, 

 dioecious; glumes 2, keeled, acute, shorter than the lemmas; 

 lemmas 3-many-nerved, acute; grain free. 



Distichlis spicata (L.) Greene. Salt-grass. Extensively creeping; leaves 

 rather rigid, smooth, involute; spikelets ovate or oblong, 8-16 mm. long, 

 smooth, 6-12-flowered. 



Along the seashore, common. 



82. FESTUCA. Fescue. 



Annuals or perennials with terminal panicles, sometimes 

 reduced to racemes; spikelets 2 -many-flowered ; glumes more or 

 less unequal, acute, keeled, the lower 1-, rarely 3-nerved, the 

 upper 3-, rarely 5-nerved; lemmas lanceolate, firm in texture 

 at least near the base, narrow, rounded on the back or slightly 

 keeled, always 5-nerved, acute or usually awned; palea usually 

 about equalling the lemma; grain glabrous, elongated, often 

 adherent to the palea. 



Annuals. 



Spikelets densely 8-13-flowered. F. octoflora. 



Spikelets loosely 1-6-flowered. 



Branches of the short panicle divergent. 



Florets 3-5 in each spikelet; only the principal rays 



divergent._ F. pacifica. 



Florets 1-3 in each spikelet; all the spikelets diver- 

 gent. F. reflexa. 

 Branches of the elongated panicle erect or appressed. 



Lemma ciliate. F. megalura. 



Lemma not ciliate. 



First glume one-third as long as second. F. myuros. 



First glume two-thirds as long as second. F. bromoides. 



Perennials. 



Callus and auricles conspicuously hairy. F. aristulata. 



Callus and auricles glabrous. 



Leaves very narrow, mostly involute. 



