82 HANDBOOK 148, U.S. DEPARTMENT OF AGRICULTURE 



rounded at tips except for protruding 

 midrib tip; commoner in e. Wash, than in 

 e. Oreg.; type locality, barren plains, 

 Columbia River; typical variety (or sub- 

 species) of Douglas rabbitbrush 



(Chrysothamnus viscidiflorus) . 

 49. Shrubs low, to 1 Y 2 feet tall ; leaves thread- 

 like to linear, to 2 inches long; flower- 

 head clusters small. 

 50. Leaves pale green, threadlike, to l)i 

 inches long, %> inch wide, 1 -nerved, 

 often twisted; flower-head clusters 

 compact; stony slopes, dry ridges, e. 



Oreg small rabbitbrush 



(Chrysothamnus viscidiflorus 

 stenophyllus). 

 50. Leaves bright green, linear, to 2 inches 

 long, }{ 2 inch wide, often 3-nerved, 

 plane, or sometimes twisted; flower- 

 head clusters often lax; plains, foot- 

 hills, e. Oreg., e. Wash. 



low Douglas rabbitbrush 

 (Chrysothamnus viscidiflorus 



pumilus). 

 44. Twigs flexible, loosely to tightly matted- woolly- 

 hairy (scraping often needed to detect hairi- 

 ness) ; leaves threadlike to narrowly linear, to 

 3 inches long, % inch wide, mostly 1 -nerved and 

 plane, often grayish- or whitish-woolly-hairy; 

 flower-head bracts keeled, 20-25, in 5 distinctly 

 vertical ranks; flower heads in roundish-topped, 

 sometimes elongate, compound end clusters; 

 "seeds" hairy; low to (usually) tall shrubs, 

 round-bushy, several-stemmed at base, with 

 tap roots; variable, often with intergrading 

 characters, poisonous to livestock under certain 

 conditions, sometimes rubber-producing; va- 

 rieties (or subspecies) often hard to tell apart. 

 rubber rabbitbrush (Chrysothamnus 



nauseosus) . 

 51. Leaves threadlike (% 5 inch wide), somewhat 

 resinous, very numerous, often nearly hair- 

 less; herbage with bad odor; twigs striate, 

 pale yellowish green with close-matted, felt- 

 like hairs; flower heads in elongate, cylin- 

 drical or pyramidal end clusters; flower-head 

 bracts often sticky, rarely hairy; to 5 feet 

 high; alkaline valleys, plains, Lake, Harney, 

 Malheur Cos., e. Oreg.; not reported from 



Wash fetid rubber rabbitbrush 



(Chrysothamnus nauseosus consimilis). 



