88 Rhodora [May 



keel above, tin* first l-iuTvod, the second a little broader and 3-nerved; 

 flowering glumes oblong, minutely erose, dentate at the rounded or 

 imperfectly 2-lobed apex, the first 5 to 6 mm. long, awned on the back 

 a little below the apex or awnless. Palea nearly as long as the glume. 

 Callus and rachilla bearded, hairs short. Awn when present rarely 

 extending beyond the apex of the glume, but varying in length from .5 to 

 3.0 mm. 



Colorado, Idaho, Washington, Oregon, and California. Tyj)e 

 locality, Twin Lakes, Colorado. 



The typical form of this sjx'cies, which tloes not extend west of the 

 Rocky Mountains, is glabrous throughout. It is rejire-sented in the 

 National Herbarium by the following specimens: Colorado, no. 093, 

 Geo. Vasey, 1868; no.' 668, Hall & Harbour, 1873; no. 333, F. E. 

 Cle77mif,<t,\H9Cy, no. 180, C. F. Baker, 1899; no. 1063, C. L. Shear, 

 1896; nos. 1449, 1482, Shear d- Bessey, 1898; Wyoming, nos. 4013, 

 4012, Aven Nehon, 1897; no. 455, E. Nelson, 1901; no. 2617, T. A. 

 Williams, 1897; no. 7787, Avert Nelmn, 1900. Montana, no. 493, C. 

 L. Shear, 1905; Utati, no. 4292, Pammel l' Baekwood, 1902. 



Trisetum Wolfii muticum (Thurb.) Scribner, n. comb. 



Trisetuvi sub.spicatvvi muiirum Thurb. in Brew. 8c S. Wats. Bot. 

 Calif. 2: 296, 1880; T. mviieim Scribn. U. S. Dept. Agr. Div. Agros. 

 Bui. 11: 50, ^r/. 10, 1898. 



Sheaths pubescent, often quite densely so, with downwardly directetl 

 hairs, leaves pubescent or pilose only upon the upper surface. Cali- 

 fornia, no. 5019, Bolander, 1866; Oregon, no. 1314, W. C. Cusirk, 

 1886; no. 2333, Cvsirk, 1899; no. 147, Criffifhs d- Hunter, 1902; 

 Washington, no. 949, W. N. Suksdorf, 1889; no. 101, Suksdorj, 1884; 

 Montana, no. 370, F. Lamsoyt-Scribner, 1883; no. 573, R. S. Wil- 

 liams, 1890; no. 3080, P. A. Rydberg, 1896; Idaho, no. 435, Heller, 

 Sandberg & McDougal, 1892; no. 1049, J. B. Leiberg, 1895, panicles 

 unusually lax; no. 2812, C. ]'. Piper, 1898 (specimen in Gray Herb.). 



Specimens with the lower sheaths finely scabro-pubescent occur 

 throughout the range of the species, connecting the pubescent with 

 the glabrous forms. 



The spikelets of T. Wolfii are less compressed and the glumes are 

 somewhat firmer in texture than in T. spicatum molle, from any form 

 of which it is readily separated by its subequal empty glumes. This 

 latter character, together with the narrower, elongated and densely 

 flowered panicles, at once distinguish Trisetum Wolfii from any form 



