47 



Moist niountaiu sides, altitudo 3,200 meters, Robinsou, Summit County, Colo. (\o. 

 1052, C. L. Sliear, August, 1896); Buena Vista, Chaffee County, Colo., altitude 

 3,500 meters (No. 1006, C. L. Shear. Aii<;nst, 1S06); Sweetwater County, Wyo., 

 altitudo 2,600 meters (No. 3828, Aven Nelson, ,Iuly 23, 18U7); Beaver Canyon, Idaho 

 (No. 301, C. L. Shear, June 27, 1895); North Park, Colo. (C. S. Craudall, Sept. 

 5, 1890); Kelso Mountain, near Torrej' Peak, Colo., altitude 3,800 meters (G. W. 

 Lettermaun, August, 1885). 



In collections this very well-marked and alpine species has often been referred to 

 S. viridula. 



STIPA TWEEDYI Scribn., u. u. {Slipa comata intermedia Scribu. Bot. Gaz. 11, 

 page 171, not Slijia intennedia Trin.) 



A densely cipspitose, glabrous, and often glaucous perennial t«> 9 dm. high, with 

 narrow, usually more or less involute leaxes and lax, nodiUng panicles, 20 to 30 

 cm. long. Sheaths smooth, lower ones generally glaucous. Ligule about 5 to 7 

 mm. long, broader than the leaf-blade. Leaves of the culm 10 to 15 cm. long, 

 3 to 5 mm. wide, minutely strigose-scabrous above, smooth beneath. Leaves of 

 the innovations narrower and longer. Base of the panicle usually included in 

 the upper-leaf sheath, its branches solitary or in pairs, naked below. Outer 

 glumes 2 to 2.5 cm. long, the first 3-nerved, the second a little longer than tJie 

 first and 5-uerved, both with long attenuate-pointed hyaline tips. Fbjwer- 

 ing glume, including the rather long densely hairy and very acute callus, 12 to 

 15 mm. long, thinly pilose hairy, apex entire. Awn about 100 mm. long, twice 

 geniculate, straight beyond the second geniculation or only slightly flcxuous, 

 scabrous throughout, very minutely pubescent toward the base. Talca as long 

 as the glume, rather broad, pilose on the back. Anthers bearded at the tips. 



Junction Butte, Yellowstone Park, altitude 1,800 meters (No. 610, F. Tweedy, 1881- 

 1885); Sheep Mountain, Laramie, Wyo., ''common on the plains and mountain 

 slopes," altitude 2,.500 meters (No. 3297, Aven Nelson, July 3, 1897) ; Dry hillsides, 

 Evauston, Wyo. (No. 2138, T. A. Williams, July 10, 1897); Tucson, Ariz. (No. 

 731, J. W. Tourney) ; Gravelly soil along railroad track, Veta Pass, Colo., altitude 

 2,650 meters (No. 821, C. L. Shear, July 15, 1896). 



This species has been confounded with Stijja comata, which it resembles in habit, but 

 in that species the flowering glume, including the callus, is about 8 to 9 mm. 

 long ; the awn is more slender, longer, and distinctly flexuous or more or less 

 curled beyond the geniculations. 



MUHLENBERGIA PALUSTRIS Scribn., sp. n. 



A very slender, much branched perennial, with numerous short and narrow leaves and 

 slender, strict panicles. Culms almost threadlike, reclining or ascending, 3 to 

 6 dm. long, smooth. Sheaths smooth for the most part shorter than the inter- 

 nodes. Ligule very short, barely 0.5 mm. long, ciliate on the margin. Leaf- 

 blades 2 to 4 cm. long, 2 to 3 mm. broad, minutely scabrous on the upper surface, 

 at least near the base. Panicles terminating the culm or the branches, 5 to 10 cm. 

 long; branches appressed, the longer lower ones 2 to 3 cm. in length, scabrous. 

 Spikelets 2 to 3 mm. long (about 2.5) exclusive of the awn. Empty glumes sub- 

 equal or the first a littlt; shorter than the second, about 0.8 nun. long. Flower- 

 iu"- glume 2.5 mm. long, linear-lanceolate, scabrous on the back, especially 

 toward the apex, barbate at the base or on the callus with rather long hairs. 

 Awn slender, straight, or slightly flexuous, 5 to 6 mm. long, Palca about as long 

 as its glume. 



Swampy grounds, Bright wood, D. C. (E. S. Steele, September, 1896). Closely 

 related to Muhle)iher;jia diffusa, from which it is readily distinguished by its 

 larger and nearly equal empty glumes. 



