22 POACEAE. 



Phalaris canariensis L. Canary grass. Annual, pale green, erect, 30-70 

 cm. high; inflorescence 2-3 cm. long; spikelets obovate, 5-6 mm. long; glumes 

 white with green veins. Introduced in waste places. 



Phalaris arundinacea L. Reed canary grass. Stout tufted perennial, 

 50-200 cm. tall; leaves flat, green, 6-10 mm, wide; panicle erect, 6-15 cm. long; 

 spikelets lanceolate, 5 mm. long. Common in wet places, often in shallow 

 water. 



34. MUHLENBERGIA. 



Perennial grasses with small 1-flowered spikelets; glumes 

 usually unequal and shorter than the lemma, acute or sometimes 

 awned; lemma narrow, 3-5-nerved, with a straight awn from 

 the apex or from between the teeth. 



Muhlenbergia sylvatica setiglumis Wats. Stems erect or nearly so, 

 60-90 cm. high, branched; leaves flat, 3-4 mm. wide, 6-12 cm. long; panicles 

 purple, narrow, 6-12 cm. long, exserted; spikelets crowded on short appressed 

 branches; glumes very narrow, scabrous, awn-pointed; lemmas scabrous and 

 tipped with an awn 6-12 mm. long. In moist rocky places, rare. 



35. ARISTIDA. 



Spikelets narrow, 1-flowered ; glumes 2, narrow, slightly keeled ; 

 lemma 1, convolute, bearing a 3-branched awn; palea short; 

 grain free, tightly enclosed in the lemma. 



Aristida purpurea robusta (Merrill) Piper. Perennial, tufted, 15-40 cm. 

 high; radical leaves numerous; stem leaves about 3, all strongly involute and 

 filiform, scabrous; panicle loose, purplish, 10-20 cm. long; awns of the flowering 

 glume capillary, 5-10 cm. long, the central slightly longer than the others. 

 JDry soil, not common. 



36. STIPA. 



Tufted grasses; inflorescence a panicle; spikelets 1-flowered, 

 narrow; lemma 1, bearing a twisted or bent awn which is spiral 

 and articulated at the base; grain narrow, free, tightly closed 

 in the lemma. All in our limits are perennials. 



Awns 10-20 times longer than the lemmas. 5. comata. 



Awns 4-7 times longer than the lemmas. 

 Awns plumose. 



Ligules 2-4 mm. long; sheaths smooth or scabrous. 5. thurberiana. 

 Ligules 1 mm. long or less; sheaths pubescent. S. elmeri. 



Awns not plumose. 



Callus very short, obtuse. S. lemmoni. 



Callus acute or acuminate. 



Awns 1-3 cm. long. 5. minor. 



Awns 3.5-6 cm. long. 5. nelsoni. 



Stipa comata Trin. & Rupr. Tufted, pale green, 40-80 cm. high; blades 

 involute; ligule 4-5 mm. long, conspicuous; panicle open, 20-30 cm. long, 

 often included at base, the branches spreading and few-flowered; glumes 5- 

 nerved, subequal, 15-25 mm. long; lemma 10-12 mm. long; awn 10-15 cm. 

 long. In the neighborhood of Spokane and Walla Walla. Common in the 

 sagebrush region of Central Washington. 



