AGROSTIDE^. 277 



spikelets that of Oryzere. It has by some been placed in the tribe 

 Oryzew. 



Tliere about 20 species found in temperate and cold countries of 

 both the Northern and the Southern Hemisphere. 



A. Spike 2 cm. long or less (a) 



a. Spike 7-13 mm. diam 1 



a. Spike 5 mm. diam 2 



B. Spike 2.5 cm. or more long (b) 



b. Empty glumes not ciliate 3 



b. Empty glumes ciliate (c) 



c. Sheath much inflated, enclosing the base of the 

 spike 4 



c. Sheath moderately or little inflated, mature spikes 



not included (d) 



d. Erect, spikes 4-8 mm. diam 5-6 



d. Erect, sj)ikes 10-15 mm. diam. ..... 7 



d. Base procumbent, spikes about 9 mm. diam. . 8 



1. A. alpinus J. E. Sm. Engl. Bot. t. 1126 (1793). Alpine 



EOXTAIL. 



A rather stout perennial, procumbent at base, 10-50 cm. high. 

 Sheaths much inflated, longer than the blades; ligule 1 mm. long, 

 obtuse; blades flat, 3-6 cm. long, 4-5 mm. wide. Spike 1-2 

 cm. long, 7-13 mm. diam., dense, branches with 4-6 spikelets. 

 Empty glumes slightly unequal, connate at base, about 3 mm. long, 

 ovate, purplish, silky all over the outer side. 



Alaska, Murdoch; Colorado, Cassiihj. 



Eocky ^Mountains. 



2. A. Howellii A' asey. Bull. Torr. Bot. Club, 15:127 (1888). 

 A. Macounii Vasey, Bull. Torr. Club, 15: 12 (1888). 



Annual ; culms 6-10 cm. high, erect or geniculate. Ligule 2 

 mm. long; lower blades narrow, exceeding the culm, the upper 

 one short, those of the culm usually 3, the upper inflated. Spike 

 oval-oblong, 1-2 cm. long, 5 mm. diam., often partially inchided. 

 Empty glumes oblong, nearly 3 mm. long, obtuse, slightly united 

 below, strongly ciliate on the keel; floral glume as long as the 

 empty glumes, smooth, obtuse, edges united to the middle or higher. 



