Figure 31. — Desert bitterbrush 

 growing on a rccu) roadcut east 

 of Independenoe J Inyo County^ 

 California. These plants 

 sprouted frorn roots exposed 

 by road construaticn. 



n. 



Purshia tridentata (Antelope bitterbrush) 



Antelope bitterbrush is an intricately branched shrub varying in stature from low 

 prostrate forms (fig. 32) to erect arborescent forms as tall as 4.6 m (fig. 33). The 

 branches of prostrate forms often root when in contact with the ground (fig. 34) . This 

 layering characteristic is common in prostrate bitterbrush throughout much of its range 

 It is a common understory shrub in ponderosa pine and lodgepole pine {Pinus aontorta) 

 types. In general, layering forms show much greater tolerance to fire than do upright 

 nonlayering forms. Fire tolerance in bitterbrush is a valuable trait. 



The yellow flowers are perigynous, perfect, showy, about 8 mm broad, and usually 

 solitary on short, lateral branchlets. Each flower has five persistent sepals, five 

 pale-yellow, spreading petals, about 25 stamens inserted on the hypanthium in one 

 series, and one or occasionally tw-o pistils (fig. 35). 



The leathery, oblong, pubescent achene is about 5 to 12 mm long and is tipped by 

 a persistent tapering style (fig. 35). 



Figure 32. — Prostrate form 

 of antelope bitterbrush 

 common over much of the 

 West, particularly in the 

 mountain brush and the 

 ponderosa pine zones. 



26 



