palea as a short commonly hairy bristle; glumes about equal, acute to acuminate; 

 lemmas shorter and usually more delicate than the glumes, usually 5-nerved with 

 the midnerve exserted as an awn, the callus bearing a tuft of hairs that are often 

 copious and as long as the lemma. 



About 80 species in temperate and cold regions of the world; especially 

 abundant in the South American Andes. 



1. Panicle nodding, rather loose and open; callus hairs copious, about as long as 

 the lemma 1. C canadensis. 



1. Panicle erect, dense or spikelike, more or less interrupted below; callus hairs 

 shorter than the lemma 2. C inexpansa. 



1. Calamagrostis canadensis (Michx.) Beauv. Blue-joint. Fig. 105. 



In small or large tussocks; culms suberect, 6-15 dm. tall, with numerous 

 creeping rhizomes; sheaths glabrous or rarely obscurely pubescent; blades numer- 

 ous, elongate, flat, rather lax, scabrous, 4-8 mm. wide; panicle nodding, from 

 narrow and rather dense to loose and relatively open (especially at base), 10-25 

 cm. long; glumes usually 3-4 mm. long, smooth or more commonly scabrous, 

 acute to acuminate; lemma nearly as long as the glumes, smooth, thin in texture, 

 the awn delicate, straight, attached, near or just below the middle and extending 

 to or slightly beyond its tip, the callus hairs abundant, about as long as the lemma; 

 rachilla delicate, sparsely long-pilose. 



Marshes, wet places, open woods and wet meadows, in N.M. (Taos Co.) and 

 Ariz. (Apache, Coconino, Graham and Pima cos.), spring-fall; Greenl. to Alas., 

 s. to W.Va., N.C., Mo., Kan., N.M. and Calif. 



A variable species that comprises several varieties. We have two segregated by 

 Fernald as follows: 



1. Spikelets 2-3.8 mm. long; glumes rounded on the back, weakly keeled, acute 

 or acuminate; lemma 1.7-3 mm. long; awn inserted near middle of 

 lemma var. canadensis. 



1. Spikelets 3.8-6 mm. long; glumes narrow, strongly keeled, distinctly acumi- 



nate; lemma 3-4.2 mm. long; awn inserted on lower third of lemma 

 var. robusta Vasey. 



2. Calamagrostis inexpansa Gray. Northern reedgrass. Fig. 105. 



Culms tufted, 4-12 dm. tall, with rather slender rhizomes, often scabrous 

 below the panicle; sheaths smooth or somewhat scabrous, the basal ones numerous, 

 withering but persistent; ligule 4-6 mm. long; blades firm, rather rigid, flat or 

 loosely involute, very scabrous, 2-4 mm. wide; panicle narrow, dense, the 

 branches mostly erect and spikelet-bearing from the base, 5-15 cm. long; glumes 

 3—4 mm. long, abruptly acuminate, scaberulous; lemma as long as glumes, 

 scabrous, the awn attached about the middle, straight or nearly so, about as long 

 as glumes, the callus hairs Vi to % as long; rachilla 0.5 mm. long, some of the 

 hairs reaching to tip of lemma. 



Meadows, marshes and wet places, in N. M. (San Juan and San Miguel cos.) 

 and Ariz. (Coconino and Apache cos.), spring-fall; Greenl. to Alas., s. to Me., 

 Va., Wash., N. M. and Calif. 



Our plant has been designated as var. brevior (Vasey) Stebbins with smaller 

 parts than in var. inexpansa; these being spikelets 3-4.5 mm. long; lemma 2.5-3.5 

 mm. long; palea 1.7-2.6 mm. long. 



27. Agrostis L. Bentgrass 

 Annual or usually perennial herbs; culms glabrous; blades flat; inflorescences 

 paniculate; spikelets one-flowered, very slightly laterally compressed; zone of 

 abscission between the glumes and the lemma (in ^. semiverticillata a zone of 

 abscission also in the pedicel below the glumes); lemma shorter than the glumes, 

 awned or awnless. 



226 



