Hybridization: Stigmas of young flowers are exserted and appear ready to receive 

 pollen before the anthers of the receptive flowers are open. Mass pollination of 

 bagged flowers just as they begin to bloom may therefore be sufficient for hybridiza- 

 tion, particularly if the flowers are self-incompatible. Other species with which 

 squawapple hybridizes naturally are not presently known. 



Distribution and Habitat: Squawapple ranges from Oregon to Colorado and California. 

 The largest populations occur in Utah where it is often an important constituent of the 

 mountain brush. It is found at altitudes from 1,220 to 2,590 m (4,000 to 8,500 feet). 



Use: Fruits of squawapple are readily eaten by small mammals, particularly 

 chipmunks and field mice. Birds, deer, and livestock show considerable preference 

 for the apples when they are available. The new twigs and foliage are readily eaten 

 by big game and livestock which may browse on the shrubs in the winter, although other 

 plant species may be preferred (Davis 1952; McKean 1956). Because of durability on 

 severe sites, this shrub might provide valuable rootstocks on which to graft closely 

 related shrubs that are more sensitive to environmental extremes. 



Purshia glandulosa (Desert bitterbrush) 



Desert bitterbrush in Utah is usually a dense, upright shrub similar in appearance 

 to Stansbury cliffrose and is often mistaken for it (fig. 30). At higher elevations 

 in California and Nevada, prostrate forms are encountered (Nord 1965). The species has 

 been regarded as a stabilized hybrid between antelope bitterbrush and cliffrose 

 (Thomas 1957; Stebbins 1959; Stutz and Thomas 1964; Stutz 1974). The evergreen leaves 

 are dark green, nearly hairless, and dotted w'ith impressed glands on the inrolled edges. 

 Leaves are cleft into 3-5 linear lobes. 



The yellow to sometimes cream-colored flowers are showy and about 20 mm broad on 

 second-year or older growth. Each flower has five persistent petals, about 25 stamens, 

 and usually two or three pistils. 



The persistent receptacle is dovs-ny haired or woolly, resinous, and dotted below. 

 Fruits are oblong achenes protruding from the receptacle. Usually three, but sometimes 

 two, finjits are produced. The fully developed fruit is 5 to 20 mm long, hard and 

 leathery, and slightly grooved, tapering to a beak that is' a vestigial plume in some 



24 



