42 POACEAE. 



Calamagrostis crassigl imis Thurb. Stems 10-20 cm. high; panicle dense, 

 3-5 cm. long; glumes ovate, acute; callus hairs nearly as long. 

 Vancouver Island to California. 



Calamagrostis hyperborea Lange. Stems tufted, 40-90 cm. high, stiffly 

 erect; leaves stiff, erect, scabrous, somewhat involute; panicle erect, narrow, 

 densely flowered, 8-12 cm. long; glumes scabrous, acute, 4-4.5 mm. long. 



Vancouver Island and eastward. 



64. AGROSTIS. BENT-GRASS. 



Annual or usually perennial grasses with small 1 -flowered 

 spikelets, usually in diffuse panicles; glumes membranous, keeled, 

 acute; lemma shorter, obtuse, hyaline, sometimes bearing a dorsal 

 awn; palea shorter than the lemma, sometimes minute or want- 

 ing; grain free, enclosed in the lemma. 



Rachilla prolonged behind the palet. 



Spikelets 3 mm. long, usually purple. A. aequivalyis. 



Spikelets 2 mm. long, usually pale. A. thurberiana. 



Rachilla not prolonged behind the palet. 

 Palet evident, 2-nerved. 



Palet one-fourth the length of the lemma; panicle con- 

 tracted. A. glomerata. 

 Palet about one-half the length of the lemma. 



Panicle contracted, usually lobed. A. stolonifera. 



Panicle not contracted. 



Plants with extensive creeping stolons, these 



bearing short leaves. A . maritima. 



Plants erect or decumbent, but without exten- 

 sive creeping stolons. 



Tall, 30-90 cm. high. A. alba. 



Dwarf, alpine, 10-20 cm. high. A. humilis. 



Palet wanting or minute and nerveless. 

 Plants spreading by rhizomes. 



Hairs at base of lemma 1-2 mm. long. A. hallii. 



Hairs at base of lemma minute or absent. 



Panicle contracted. A. pollens. 



Panicle open. A . foliosa. 



Plants without rhizomes. 



Panicle narrow, some of the branches short and 



spikelet-bearing to the base. 



Lemma awned. A. microphylla. 



Lemma awnless. 



Panicle 5-30 cm. long; lowland plant. A. exarata. 



Panicle 3-6 cm. long; alpine plant. A. rossae. 



Panicle open, usually without short branches spike- 

 let-bearing to the base. 



Awn of lemma attached near the base. A . howellii. 



Awn of lemma, if present, attached at or above 



the middle. 

 Lemma awnless. 



Panicle very diffuse. A . hyemalis. 



Panicle loose but not diffuse. A . oregonensis. 



Lemma awned. 



Awn straight, included or but slightly 



rted. A . melaleuca. 



Awn exserted, bent. A . longiligula. 



