Rydberg: Rocky Mountain flora 607 



. Poa confusa Rydb. sp. nov, 



A tufted bunch-grass with intravaginal h-inovations ; sheaths of 

 the basal leaves short, striate, glabrous; blades 1-2 dm. long, 

 2-$ mm. wide, flat or involute, puberulent; culm-leaves several ; 

 sheaths i-i-S dm. long; blades about i dm. long; ligules broadly 

 ovate or rounded, obtuse or acutish, about 2 mm. long ; culm 6-9 

 dm. high ; panicle narrow, 1-1.5 ^"i- ^^^gf dense; branches short, 

 strongly ascending ; spikelets 7-8 mm. long, usually 4-flo\vered ; 

 empty glumes lanceolate in side-view, shining, minutely strigulose 

 above; flowering glumes narrow, about 3.5 mm. long, obtuse or 

 rounded at the apex, rounded on the back below, strigulose, yel- 

 lowish-green with brownish scarious margin. 



This species has been confused with P, laevigata^ P, Incida and 



P. nevadensis. It differs from the first two by the short and 



broad ligules (in both the ligules are lanceolate and acuminate), 



and from the last by the empty glumes and in being scarcely 



scabrous. In P, nevadensis the empty glumes are strongly 



nerved, elongated-lanceolate, almost equaling the oblong, very 



scabrous flowering glumes ; in P. confusa they are faintly nerved, 



broadly lanceolate, shorter than the flowering glumes, P. confusa 



grows in open "parks" and on hills from Nebraska and Montana 



w 



to Colorado. As the type may be assigned : 



Wyoming : Medicine Bow Mountains, Albany County, July 

 28, 1900, Aven Nelson 778 j. 



^ Poa truncata Rydb. sp. nov. 



A species related to the preceding but stiffer ; basal leaves 

 withering early; sheaths of culm-leaves 10-15 cm, long, with con- 

 spicuous hard auricles at the mouth ; ligules very short, about i 

 mm. long, truncate; blades I-2 dm. long, 2-3,5 mm. wide, 

 scabrous on the back ; culm about 9 dm. high, stiff; panicle about 

 1.5 dm. long, narrow, with almost erect scabrous branches ; spike- 

 lets 3-5 -flowered, 7-9 mm. long; empty glumes 5-6 mm. long, 

 tinged with purple, scabrous on the nerves; flowering glumes nar- 

 row, about 5 mm. long, straw-colored or tinged with purple, strigu- 

 lose throughout and slightly scabrous on the veins. 



The short truncate ligules separate this from the preceding 



and all other related species. 



Colorado: Dillon, Summit County, August 26, 1896, F. E. 



Clements ^7 J, 



