GRASSES OF IOWA. 401 



The Glycerin grandis, another ally to the foregoing, is common through- 

 out the northern states to Colorado, California, British Columbia and 

 Sitka, Alaska. An allied species, G. fluitans is cosmopolitan, occurring in 

 Europe, Asia, Africa and Australia. It is common throughout northern 

 United States, south to Arkansas and Tennessee. The genus Bromus is 

 comopolitan, common especially in the Northern Hemisphere, a few oc- 

 curring in the tropics, well represented in the Rocky Mountains and 

 Europe. The Bromus inermis of Hungary and Switzerland has a near 

 relative in the northern Rockies, the Bromus Pumpellianus. The Bro- 

 mus secalinuSj B. arueiisis and B. tectorum are cosmopolitan weeds. 



The genus Hordeum occurs in Asia, Europe, North Africa, North 

 and South America. The //. nodosum found in northeastern low 

 widely distributed in the United States from Ohio to Minnesota and 

 Texas; common in the Rocky Mountain region to Nevada, California 

 and Vancouver. The Hordeum jubatum along the Arctic coast, the 

 Great lakes and westward to the plains and the Rocky Mountain region, 

 I tab, Nevada, to Vancouver, Saskatchewan, Peace River, also in south- 

 ern Russia and eastern Siberia. 



The genus Elymus generally in temperate regions except Australia 

 and South Africa. Three species, Elymus striatus, E. Canadensis, ami 

 E. Virginicus are common on the Atlantic coast and in the Mississippi 

 Valley. The E. condensatus is a Rocky Mountain species abundant in 

 the flood plains of streams. Sitanion, which is closely allied to Elymus, 

 is a development of the North American plain, perhaps reaching south- 

 western Minnesota. The numerous species made of this genus will 

 scarcely hold. Another ally of Elymus is Asprella with four species: 

 North America two, Siberia one, New Zealand one. The Asprella 

 Hystrix is of wide distribution in eastern North America, while A. Cali- 

 fornica has a somewhat limited range on the Pacific coast. 



The genus \gropyron, generally distributed in temperate regions, is 

 conspicuous on the plains and in the Rocky Mountain region. 



The ./. occidentale and A. caninum in northern United States and 

 Canada, the latter also in Europe, Asia (Siberia and Himalayas). ./. 

 glaucum, a maratime species of Europe, Asia and eastern United States. 

 The A. re pens a common weed in Europe and northern United States. 



Of the large number of species of Festuca described, one hundred 

 and twenty-nine are credited to Europe by Richter, however, Hackel give- 

 only eighty species, found chiefly in temperate regions. The Festuca 

 ovina and E. rubra are cosmopolitan, common only in northern portion- 

 of the United States and in the Rocky Mountains; southward these 

 species have become naturalized. The Festuca octoflora common 



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