306 MISC. PUBLICATION 200, U. S. DEPT. OF AGRICULTURE 



having lemmas sparsely pilose on the back. Known only from 

 Nanaimo, Vancouver Island (Macoun 78825). 



7. Danthonia unispicata Munro. ONE-SPIKE OATGRASS. (Fig. 607.) 

 Culms 15 to 25 cm tall, in dense spreading tufts; sheaths and blades 

 pilose, the hairs on the sheaths spreading or reflexed; panicle reduced 

 to a single spikelet or sometimes 2, rarely 3, spikelets, the lower 

 spikelets usually reduced, their pedicels appressed or ascending, the 

 long pedicel of the terminal spikelet jointed with the culm; spikelets 

 on the average smaller than in D. calij 'ornica. 01 Open or rocky 

 ground, Montana to British Columbia, south to Wyoming and Cali- 

 fornia (fig. 608). 



TRIBE 5. AGROSTIDEAE 



61. CALAMAGK6STIS Adans. REEDGRASS 



Spikelets 1 -flowered, the rachilla disarticulating above the glumes, 

 prolonged behind the palea (in our species, except Calamagrostis 

 epigeios) as a short, commonly hairy bristle; glumes about equal, 

 acute or acuminate ; lemma shorter and usually more delicate than the 

 glumes, usually 5-nerved, the midnerve exserted as an awn, the callus 

 bearing a tuft of hairs, these often 

 copious and as long as the lemma. 

 Perennial, usually moderately tall 

 grasses, mostly with creeping rhi- 

 zomes, with small spikelets in 

 open or usually narrow, some- 

 times spikelike panicles. Type 

 species, Arundo calamagrostis L. 

 Name from Greek kalamos, a reed, 



and agrostis, a kind of grass, the type species being a 

 reedy grass. Our species (except C. epigeios) belong to 

 the Section Deyeuxia, in which the rachilla is pro- 

 longed. In Section Epigeios, of the Old World, the 

 rachilla is not prolonged. 



__, Several species are important native forage grasses. 



x 5. "(Davy I Pinegrass, C. rubescens, is a leading range grass in the 

 mountains of Oregon and Washington. Blue joint, C. 

 canadensis, is a source of much of the wild hay of Wisconsin and 

 Minnesota. On the plains and bench lands of Wyoming and north- 

 ward, C. montanensis furnishes forage, especially when young. In low 

 wet lands of the Northern States C. inexpansa is grazed especially by 

 horses and cattle. 



la. Awn longer than the glumes, geniculate. 



2a. Panicle open, the branches spreading, naked below. 



Blades scattered, 5 to 9 mm broad, flat. Plant mostly more than 1 m 



tall 1. C. BOLANDERI. 



Blades mostly basal, mostly not more than 2 mm wide, often involute. 

 Awn about 1 cm long, much longer than the glumes; blades nearly or quite 



as long as the flowering culms 2. C. HO WELLII. 



Awn only a little exceeding the glumes; blades much shorter than the 



culms, capillary, sulcate, folded 3. C. BREWERI. 



2b. Panicle compact, the branches appressed, floriferous from base. 



Blades scattered, broad and flat, 6 to 10 mm wide 4. C. TWEED YI. 



Blades mostly basal, firm, narrow, becoming involute. 



Glumes about 1 cm long, gradually long-acuminate; awn nearly 1 cm long 



above the bend 5. C. FOLIOSA. 



Glumes 6 to 8 mm long, abruptly acute or acuminate; awn usually less 

 than 5 mm above the bend _. 6. C. PURPURASCENS. 



FIGURE 608. Distribution 

 of Danthonia unispicata. 



FIGURE 607. Dan- 

 thonia unispicata, 



