Studies on the Rocky Mountain Flora.— V. 



By P. A. Rydberg 



Sporobolus aristatus sp. nov. 



Vilfa de pauper ata var. filiformis Wats. King's Exp. 5 : 376, in 



part (as to the awned form). 1871. Not Thurb. 



Perennial with short branching rootstock. Culm usually only 

 4-6 cm. high : internodes short, usually covered by the open strongly 

 striate sheath ; ligules lanceolate, acute, about 1.5 mm. long : leaf- 

 blades 8-14 mm. long, and about 1 mm. wide, striate and puberu- 

 lent on the upper surface : panicle few-flowered, very narrow, with 

 short erect branches ; empty glumes almost equal, or the inner 

 slightly longer, 1-1.25 mm. long, less than half as long as the 

 flowering glume, ovate, acutish or obtuse and somewhat erose at 

 the apex : flowering glume about 2.5 mm. long, strongly veined, 

 long-strigose on the veins and tipped with an awn .5-1 mm. long ; 

 palet almost equal to the flowering glume (awn excepted) in 

 length, acuminate, but not awned, strigose. 



This species is closely related to 5. filiformis (Thurb.) Rydb. 

 differing in the lower habit, less exserted panicle, firmer empty 

 glumes and the presence of a distinct awn. It grows in wet places 

 at an altitude of 2000-2500 m. 



Wyoming: Big Horn Mountains, Sheridan Co., 1899, F. 

 Tweedy, 21 p6 (type); Spread Creek, 1897, 2j. 



Utah: Bear River Canon, 1869, S. Watson, 1281. 



Poa platyphylla Nash & Rydb. 



Poa trivialis var. occidentalis Vasey, Desc. Cat. Grasses 85. 



1885, Not Poa ft* 

 Poa occidentalis 



1878. 



1893. 



Carex ebenea sp. nov. 



Perennial by a cespitose rootstock. Stem 2-4 dm. high, 

 strongly striate ; sheath with a conspicuous membranaceous ligu- 

 lar portion, ligule proper rounded, about 2 mm. long ; leaf-blades 

 flat, 1-2 dm. long, 3-6 mm. broad, strongly nerved : spikelets 

 about 1 cm. long in a dense globular or rounded-conical head : 



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