100 MISC. PUBLICATION 303, U. S. DEPT. OF AGRICULTURE 
A small shrub; occurs on sandy, alkaline plains; flowers August-September: 
greatly increased by overgrazing. Of some slight value as browse for livestock 
where other feed is not available. 
Chrysothamnus humilis, see Chrysothamnus viscidifiorus. 
Chrysothamnus latifolius, see Chrysothamnus viscidifiorus. 
Chrysothamnus leiospermus, see Chrysothamnus nauseosus. 
Chrysothamnus linifolius, see Chrysothamnus viscidifiorus. 
Chrysothamnus marianus, see Chrysothamnus viscidifiorus. 
Chrysothamnus monocephalus, see Chrysothamnus parryi. 
Chrysothamnus nauseosus (Pallas) Britt. Rubber rabbitbrush, 
Chrysocoma nauseosa Pallas. 
Ranze:'4, 6, 7,:c. & 44, 12) 13, Aa ws: 
Site: Dry, sun. 
Fruit: Achene. 
A small to large shrub; flowers September—December; root system deep; re- 
produces readily from seed and grows vigorously when transplanted, even when 
crowns are divided; forms basal sprouts after cutting; contains on the average 
2.8 percent of rubber, although this may increase to 6.5 percent in individual 
plants; the most constant producers are those forms inhabiting alkali soils; it 
has been estimated that 300 million pounds of good-grade rubber are represented 
in this country by this species, but extraction is not yet commercially profitable. 
Twenty subspecies or varieties are included within this species; they rep- 
resent the species in various sections of the Great Basin and adjacent areas. 
C. nauseous includes the following forms: 
C. bigelovit (Gray) Greene, C. collinus Greene, C. concolor Rydb., C. consimilis 
Greene, C. glareosus Rydb., C. graveolens (Nutt.) Greene, C. leiospermus (Gray) 
Greene, C. occidentalis Greene, C. oreophilus Nels., C. pinifolius Greene, 
C. pulcherrimus Nels. (more robust), C. salicifolius Rydb., C. speciosus Nutt., 
C. turbinatus Rydb. 
Certain forms, as consimilis and viridulus, form pure stands on alkali flats; 
in general the important varieties are subclimax dominants of the sagebrush 
association. 
Observations: Northward it furnishes an important winter browse for elk and 
perhaps moose; California mule deer. Value as browse for livestock depends 
on local conditions; palatability ordinarily very low; probably poisonous when 
eaten exclusively ; a not infrequent indicator of overgrazing. 
Chrysothamnus newberryi, see Chrysothamnus parryi. 
Chrysothamnus occidentalis, see Chrysothamnus nauseosus. 
Chrysothamnus oreophilus, see Chrysothamnus nauseosus. 
Chrysothamnus paniculatus (Gray) Hall. Sticky rabbitbrush. 
Bigelovia paniculata Gray, Ericameria paniculata (Gray) Rydb. 
Range: 10. 
Site: Dry, sun. 
Fruit: Achene. 
A small to large, brittle-twigged shrub; flowers May—October; resistant to 
low temperatures; grows in extremely poor soils; rubber content about 2.5 per- 
cent, but strains may be found containing a higher percentage. 
Chrysothamnus parryi (Gray) Greene. 
Linosyris parryi Gray, Bigelovia parryi Gray. 
Range: 4, 8, 9, 10, 13, 12, 18, 15. 
Site: Dry, well-drained, sun. 
Fruit: Achene. ‘ 
A small shrub occurring on sandy or gravelly soils: an indicator of over- 
grazing. Ten subspecies or varieties are recognized which do not separate on 
stable characters but which are more or less separated geographically; the 
whole complex is here considered a single major species. It includes among 
others: C. asper Greene, C. newberryi Rydb. C. vulcanicus Greene, C. mono- 
cephalus Nels. and Ken., and C. wyomingensis Nels. 
Chrysothamnus pinifolius, see Chrysothamnus nauseosus, 
