Rvdberg : Rocky Mountain flora 607 



Poa confusa Rydb. sp. nov. 



A tufted bunch-grass with intravaginal innovations ; sheaths of 

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

 2-3 mm. wide, flat or involute, puberulent ; culm-leaves several ; 

 sheaths 1-1.5 dm. long ; blades about 1 dm. long ; ligules broadly 

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

 dm. high ; panicle narrow, 1-1.5 dm. long, dense ; branches short, 

 strongly ascending ; spikelets 7-8 mm. long, usually 4-flovvered ; 

 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. lucida 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 

 to Colorado. As the type may be assigned : 



Wyoming : Medicine Bow Mountains, Albany County, July 

 28, 1900, Aven Nelson 7j8y. 



Poa truncata Rydb. sp. nov. 



A species related to the preceding but stiffer ; basal leaves 

 withering early; sheaths of culm-leaves ic— 15 cm. long, with con- 

 spicuous hard auricles at the mouth ; ligules very short, about 1 

 mm. long, truncate ; blades 1—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 j jj. 



