Use .--This shrub may provide an important supply of browse to both game and live- 

 stock, particularly during late fall and winter after more desirable forage has been 

 utilized. Throughout the Great Basin, low rabbitbrush ., especially the flowering shoots, 

 provides good sheep feed. In California small amounts of low rabbitbrush were found in 

 10 to 14.8 percent of a large number of deer stomachs examined between October and 

 January (Sampson and Jespersen 1963) . There is much variation in palatability among 

 the different subspecies. Some may be heavily utilized, whereas others are utilized 

 little if at all (McArthur and others 1974) . Subspecies stenophyllus on rocky foothills 

 is often heavily used and sometimes destructively so, with animals preferring mature 

 or partially mature plants to green immature ones. On a Utah winter range, this sub- 

 species averaged up to 11,31 percent by weight of the diet of sheep (Cook and Harris 

 1950; Cook and others 1954). We have observed substantial use on ssp. lanoeolatus in 

 widely scattered areas of Utah and Nevada. 



Antelope, elk, and bighorn sheep, as well as deer and livestock, show varying 

 preferences for low rabbitbrush, depending on season, locality, and subspecies. 



This species, like rubber rabbitbrush, increases rapidly and vigorously on over- 

 grazed or otherwise disturbed sites. Some subspecies such as stickyleaf low rabbit- 

 brush (ssp. visoidiflorus) and mountain low rabbitbrush (ssp. lanoeolatus) adapt well 

 to higher elevations while other subspecies such as narrow-leaf low rabbitbrush (ssp. 

 stenophyllus) and hairy low rabbitbrush (ssp. puberulus) do best in lower desert and 

 foothill habitats (Plummer 1977) . Low rabbitbrush is valuable for revegetating de- 

 pleted rangelands and other disturbed sites, such as strip mines and roadsides. 



Subspecies . --Chrysotharmus viscidiflorus ssp. lanoeolatus (mountain low rabbit- 

 brush) is a small shrub from 2 to 5 dm tall (figs. 56a, 57) . Its branches are straw- 

 colored or gray and are finely pubescent. Flower heads are borne in small compact cymes 

 with densely pubescent branches. Involucral bracts are 5 to 6.5 mm long, lanceolate to 

 oblong, obtuse, and glabrous to pubescent. Achenes are densely strigose. On the basis 

 of his systematic investigations in the genus Chrysotharmus , L. C. Anderson (letter dated 

 5/17/76) recommended placing the former ssp. elegans in synonomy with C. viscidiflorus 

 ssp. lanoeolatus. Our chromatographic work (McArthur and others 1978) supports this 

 consolidation. Specimens we collected as elegans could easily be placed in ssp. 

 lanoeolatus or puberulus, depending on leaf width characteristics. Mountain low rabbit- 

 brush is widespread and fairly common in dry foothill and mountainous habitats from 

 1,520 to 3,200 meters (5,000 to 10,500 feet) ranging from British Columbia, east to 

 Montana, and south to New Mexico, Utah, and Nevada. This subspecies may be found 



Figure 57. — Mountain low 

 rabbitbrush (C. viscidi- 

 florus ssp. 1 lanoeolatus J 



growing at the Snow 

 Field Station. 



56 



