608 THE GLACIAL LAKE AGASSIZ. 



Stipa spartea Trin., deservedly named "porcupine grass," but more commonly 

 called "wild oats" in Miuuesota and tlie Dakotas; abundant on the dry prairie, 

 especially in South Dakota. 



Stipa viridula Trin., extending east, on sandy alluvial soil of bottom-lands, to 

 the Red River; also common westward on the general jirairie. 



Miihleitbergia glomerafa Trin. (chiefly the var. rumosa Vasey), plentiful on moist 

 land; frequently persisting as a weed in wheat fields aud other cultivated ground. 



Sporobolus cusphlatus Ton-., common on dry portions of the prairie in the Dakotas, 

 Manitoba, and Assiniboia. 



Sporoholus heterolcpis Gray, also i)lentiful from Nebraska to northwestern 

 Manitoba. 



Agrostis alba L., var. vulgaris Thurber, indigenous and common on moist land, 

 especially northward. 



Agrostis scabra Willd., abundant along rivers, so that in late summer the wheel 

 rnts of roads are often filled with its dead panicles, broken off and blown thither by 

 the wind. 



Dcyeuxia canadensis Hook. f. {Calamagrostis canadensis Beauv.), abundant on wet 

 meadows bordering streams, especially in the forest region. 



Begeuxia neglecta Kunth {Calamagrostis stricta Trin.), plentiful on similar ground 

 throughout the prairie region west of Winnipeg. 



Ammophila longifolia Benth. {Calamagrostis longifoUa Hook.), which binds the 

 sand dunes along the south shore of Lake Michigan, is generally abundant on sandy 

 ridges through all the prairie region from the Red River west to the Rocky Mountains. 



Avcna pratcnsis L., var. amerivana Scribner, common from Portage la Prairie 

 westward. 



Danthonia intermedia Vasey, common from the Red River to the sources of the 

 Qu'Appelle; also found at the east in Anticosti and Gaspc, extending west to Van- 

 couver Island. 



Bouteloua oligostachya Torr., the most valuable and widely spread of the "buf- 

 falo grasses," observed as the main species of grass on large tracts of the prairie 

 between Devils Lake and the Souris Ri\er; described by Vasey and Havard as the 

 commonest species on the great plains, surpassing all others in its importance as 

 pasturage for stock of all kinds, even in winter, when its dried tufts or bunches still 

 retain their nutritive quality. 



Phragmites communis Trin., abundant, often 10 to 15 feet high, in the edges of 

 lakes. A prostrate stem 20 feet long, rooting at the joints, was observed at Red Lake, 

 Minnesota. 



Kceleria cristata Pers., very abundant on the drier portions of the country, 

 aflbrding good pasturage; estimated by Lieberg as constituting fully half of the 

 entire growth of grass along the Northern Pacific Railroad between the James aud 

 Yellowstone rivers. 



