67 



Tetraneuris lanata Greene. — A perennial plant with numerous root-leaves and 

 naked stems bearing single yellow heads, 3 to 4 inches high. Excellent speci- 

 mens were secured of this good species which until recently has heen suppressed 

 by merging it into T. acaulis Greene. (Jreeu River, May 31 (3068). 



Tanacetuni nuttallii T. and G. (Nuttall's Tansy). ^xV suuxll, cjespitose perennial 

 producing little spherical heads of flowers on slender, naked stems, 2 to 3 inciics 

 long. Green River, June 1 (3049). 



Artemisia cana Pursh. (White-lkafed .Sage-bru.sh). — A small shrub, 2 to 3 feet 

 high, with slender branches and long, entire leaves, grayish-white in coloi'. < )f 

 the sage-brushes this is the best Ibrage jdant. Creston, August 28 (4421); Hat 

 Creek, August 20 (42.50). 



Arteniisla pedatifida Nutt. — A low, matted sage occurring frequently on the alka- 

 line Hats and in the clayey draws. Though small and inconspicuous it probably 

 furnishes considerable forage for sheep. Bitter Creek, .June 2 (3103). 



Artemisia spinescens Eaton (Bud BRr.sii; Spiny SAOE-BRrsH). — Early in the 

 spring this forms a low, spherical clump of tender leaves and flower buds that 

 are much relished by sheep. Green River, May 30 (3028). 



Artemisia trifida Nutt. — A small shrub with deeply three-cleft leaves, not common; 

 principally in the hill region. Not sufficiently abundant to have any economic 

 significance. 



Artemisia tridentata Nutt. (Common Sage-brcsii). — The best known shrub of the 

 great, arid West, varying immensely in size in diftereut situations, from a dwarf 

 shrub less than a foot high to almost tree-like proportions; common on the 

 plains and at increasingly higher altitudes up to the subalpine parks of the 

 mountains. 



Artemisia sp. ( ?). — A small, almost herbaceons form with slender stems and numer- 

 ovis, entire leaves was found growing interspersed among the grasses in a wet 

 draw among the hills. It may possibly be a form of A. mexicana Willd., but 

 more probably is new. If it could be grown as a crop it looks as if it might have 

 forage \alue. 



Senecio canus Hook. — A perennial herb of no value as forage; in the draws at 

 Green River, June 1 (3070). 



Tetradymia canescens DC. — A closely branched shrub, 9 to 1.5 inches high, leaves 

 and branches whitish with flne hair, producing dense clusters of yellow flowers. 

 Probably eaten to some extent by sheep, the tender twigs in the winter, the 

 young leaves and twigs in late spring. Bitter Creek, July 12 (3()99) ; Point of 

 Rocks, August 30 (4432). 



Tetradymia canescens inermis Gray. — Very similar to the preceding, but smaller 

 and more compactJy branched. Bitter Creek, June 2 (3107). 



Tetradymia nuttallii T. & G. — An intricately branched shrub, 1 to 3 feet high, less 

 whitened with hair than the pi-eceding, horridlj' prickly with rigid, sharp, 

 divergent spines; the young branches soft and freely nipped otf by sheep. Greeu 

 River, May 31 (3061); Fort Steele, June 5 (3134); Bitter Creek, July 12 (3697). 



Tetradymia spinosa H. & A. (see PI. Ill, fig. 2). — More slender and less l)ranched 

 than the preceding, the branches perfectly white, with tomentum or matted wool; 

 the leaves are dropj)ed early in the season and the compact, naked mass of white 

 twigs form a very conspicuous part of the vegetation on the otherwise often 

 rather naked slopes and hills. Though the older stems are rather sharp-spiny, 

 yet this forms a valuable constituent of the winter forage forsheep and antelope. 



Cardiius leiocephalus Il(dler. — A small thistle with white, woolly ]ea\es: not abun- 

 dant. Bitter Creek, July 12 (3.529). 



