42 POACEAE. 



Calamagrostis crassiglumis 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. aequivalvis. 



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. 



Palet about one-half the length of the lemma. 

 Panicle contracted, usually lobed. 

 Panicle not contracted. 



Plants with extensive creeping stolons, these 



bearing short leaves. 



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 12 mm. long. A. hallii. 



Hairs at base of lemma minute or absent. 



Panicle contracted. A. pattens. 



Panicle open. A.foliosa. 



Plants without rhizomes. 



Panicle narrow, some of the branches short and 



spikelet-bearing to the base. 

 Lemma awned. 

 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 



exserted. A.melaleuca. 



Awn exserted, bent. A . longiligula. 



A. glomerata. 

 A. stolonifera. 



A. maritime,. 



A. micro phylla. 



