50 



15 KQin. long, 3 to 4 niin. wide, loug accumiuate-pointcd, miiiTitely scabrous 

 on the nuder surface, glabrous above. Panicles rather densely lowered, the 

 main axis and primary branches minutely pubescent; the longer branches 2 to 4 

 cm. in length, naked below, the shorter ones flower-bearing to the base. Spike- 

 lets 4 to 5 mm. long, 1- to 2-flowered, with a hairy prolongation of the rachilla 

 beyond the second flower. When 1-flowered, this jirolongation of the rachilla 

 may bear an imperfect glume and awu. Empty glumes une(|ual, acuminate- 

 pointed. The first 1-nerved and about 3 mm. long; the secoud 3-nerved and 

 about 4 mm. long or nearly equaling the si>ikelet. Flowering glumes minutely 

 scabrous on the back. The lirst about 4 umi. long, narrowly lanceolate, acute or 

 slightly 2-cleft at the apex, awned below the apex. Awn straight and 1 to 



3 mm. long. I'alea hyaline, nearly as long as the 

 glume, arcuate below, 2-toothed at the apex. Cal- 

 lus shortly barbate, joints of the rachis pilose-hairy. 

 Among rocks. Las Animas Canyon below Silverton, 

 Colo. (No. 1214, C. L. Shear, August 4, 1897), alti- 

 tude 2,700 meters. An elegant grass and appar- 

 ently a well-marked species, nearly related to 

 T. woljii Vasey (tig. 9), which is distinguished 

 by its shorter, narrower leaves, perfectly smooth 

 culms and sheaths, smaller and more loosely flow- 

 ered and less compressed spikelets and longer 

 hairs on the joints of the rachilla. T. wolJU was 

 collected at Twin Lakes, C«do., by .John Wolf in 

 1873, and sijecimens exactly resembling tlie type 

 were collected in willow thickets. Twin Lakes, 

 Colo., by Mr, Fred E. Clements (333), August 20, 

 1896. These are the ouly specimens in the Nationiil 

 Herbarium referable to this species, which is 

 fairly well tigured in Bot. Wheeler Ex])c(Iit io7i, 

 plate 27 (1878). 

 Trisetum arginUum is distinguished from the closely 

 allied T. moiitanum Vasey by its shorter, straight 

 awns, which are inserted higher up on the glume. 

 Trisetum muticum (Boland.) Scribu. (tig. 10). Trisetum 

 ,siiln:ipic((tuiii var. nialiciiia Boland. in herb. Thurb. 

 in S. Wats. Bot. California 2:296, Tritfclmn woljii 

 Vasey (in i)art). Trinetum lu-andc(jn Scribu. in Bull. 

 Torr. Bot. Club 10:64. This species is in every 

 way stouter than Trisetum wolfii, with broader and 

 longer leaves and larger and more densely flow- 

 ered panicles. The outer glumes are more nearly 

 equal, and the flowering glumes tirm in texture, with rougher surface. Trise- 

 tum hrandegvi was based on a robust form of the sjiccics. 

 Trisetum melicoides (Mx.), Scribu., Coult. Bot. Caz. 1887, p. 167 {.lira meUcoidea 

 Michx., (iraphcphorum meViroides Bcanv.) belongs in this group of species. 



ZEUGITES PRINGLEI Scribu., sp. n. (I'l. VI.) 



A slender, branching perennial, 3 to 6 dm. loug, with broadly ovate, acute. ](etiolate 

 leaves aiul capillary jjanicles abou't 8 to 10 cm. long. Culms and sheaths glabrous, 

 smooth. Ligule 1 to 2 mm. long. Leaf iietiolcs very slender, about 1 cm. in 

 length. Leaf-blades glabrous, 3 to 4 cm. long and 2 ( in. broad, rounded at the 

 base, transverse veins conspicuous on the under surface. Branches of the ])aniel(> 

 spreading or divergent, very slender. Spikelets 2- to 3-tio\V('red, about 7 mm. 

 long. Outer glumes about 2 mm. long, equal iu length; the first 5-nerved, the 



Fig. 7. — Agrostin pixluduxa 

 Scribu.: a, empty };laiiifs; 6, 

 flowering glume, sbowing a 

 small palea and tliree stamens. 



