Figure 9. — FoumSing saltbush utricle variation in half-sib family growing at Snow Field 



Station, Ephraim, Sanpete County, Utah. 



Garrett saltbush (Atriplex garrettii) , a form closely related to fourwing saltbush, 

 also has four-winged utricles. It differs by being a subshrub under 40 cm tall with 

 wider leaves, oval or broadly elliptical in shape. 



The taxonomic status of Garrett saltbush is uncertain. Some authors (Hall and 

 Clements 1923; Harrington 1954; Brown 1956) consider it a subspecies of fourwing salt- 

 bush. Other authors (Kearney and Peebles 1960; Hanson 1962; Plummer and others 1966b) 

 accept it as a separate species. Garrett saltbush is a narrow endemic. It occurs only 

 along the Colorado River and its tributaries in southern Utah and closely adjoining 

 areas . 



Hybridization: Fourwing saltbush readily hybridizes in nature with other Atriplex 

 species (Hanson 1962; Plummer and others 1957; Plummer and others 1966a; Drobnick and 

 Plummer 1966), (fig. 10 and 11). Our preliminary results and the results of Drobnick 

 and Plummer (1966) indicate that artificial pollination of pistillate fourwing saltbush 

 with pollen from shadscale saltbush {Atriplex conferti folia) , Gardner saltbush (^4. 

 gardneri) (fig. 12), mat saltbush (A. corrugata) , winterfat [Ceratoides lanata) , black 

 greasewood {Sarcobatus vermiculatus) , spiny hopsage {Grayia spinosa) , and spineless 

 hopsage {G. brandegei) has resulted in viable seed. It is not known whether this 

 pollination produces genuine hybrid seed in all cases. It may stimulate asexual repro- 

 duction in which seeds develop from unfertilized eggs or from somatic cells associated 

 with egg cells. 



Table 1 shows percent germination of seed obtained from the various crosses 

 attempted during 1968 and 1969. Several important incidents occurred that reduced 

 production of putative hybrid seed between fourwing saltbush and shadscale saltbush, 

 mat saltbush, and spineless hopsage. During 1967, heavy winds and rain detached many 

 of the sacked branches, and failure to cover the treated branches with cloth sacks 

 prior to seed maturation resulted in losses attributed to rodents, deer, and natural 

 drop. A late spring frost in 1968 killed most of the fruit at several locations. A 

 large number of seedlings were lost in a greenhouse because of excessive heat and 

 dehydration during the winter of 1969-70. 



7 



