604 Rydberg : Rocky Mountain flora 



open ; branches usually in pairs, in age reflexed ; the lowest 4—5 cm. 

 long, bearing the sp'ikelets near the ends ; spikelets 4—5 mm. long, 

 mostly 3-flovvered ; empty glumes lanceolate in side view, strongly 

 veined, usually purple, acuminate ; flowering glumes lanceolate, 

 sharp-acuminate, greenish below, then purplish and scarious at the 

 apex ; cobweb present but scant ; internerves glabrous and nerves 

 pubescent. 



The type specimens were determined by Professor Scribner as 

 P. arctica, but it differs from that species in the smaller more 

 sharply acuminate flowering glumes and their glabrous inter- 

 nerves. These characters would place it closer to P. rcflcxa. 

 The latter species is, however, taller, and the intermediate nerves 

 of the flowering glumes are glabrous. 



Colorado : Stephen's Mine, below Gray's Peak, Aug. 23, 

 1895, P. A. Rydberg 2jf^j (type) ; near Pagosa Peak, Aug. 1899, 

 C. F. Baker 2og (determined as P. reflexa) ; high mountains about 

 Empire, 1892, H. N. Patterson 2'j2. 



Poa macroclada Rydb. sp. nov. 



Perennial with a horizontal rootstock ; culm 6-8 dm. high ; 

 sheaths 5-15 cm. long, rather loose, strongly striate, slightly scab- 

 rous ; ligules ovate, acute, about 2 mm. long; leaf-blades 7—10 

 cm. long, 2 mm. or less wide, flat, glabrous, firm and dark-green ; 

 panicle 2-3 dm. long, open ; branches in 3's-5's, in fruit reflexed 

 or spreading, the lower often i dm. long, with the spikelets near 

 the ends ; spikelets often about 5 mm. long, 2- or 3-flowered ; 

 empty glumes lanceolate, very acute, more or less purplish ; flow- 

 ering glume lanceolate, acute or acuminate, glabrous, slightly pur- 

 ple-tinged ; intermediate veins faint and cobweb scant. 



This species is related to P. apcrta, but differs in the long slen- 

 der branches of the panicle and the glabrous flowering glumes. 



Colorado: Roger's, Gunnison Watershed, August 14, 1901, 

 C. F. Baker S02. 



Poa interior R}'db. sp. nov. 



Poa iieiiioralis Scribn. Bull. U. S. Div. Agrost. 17: 250. 1899. 



Not P. nevwralis L. 1753. 

 1 Poa eaesia Coult. Man. Rocky Mt. Reg. 421. 1885. Not P. 



t-rtcw/^-? Smith. i8co. 



The grass common throughout the Rocky Mountain region 

 and extendiiiLj in the north from Alaska to the Dakotas and een- 



