Table I. -Seed and seedlings obtained by artificially pollinating pistillate flowers 

 of fourwing saltbush (Atca)^ with pollen from winterfat (Cela), shadscale (Atco) , 

 mat saltbush (Atco"^), black greasewood (Save) , Gardner saltbush (Atga) , and spineless 

 hopsage ( Grbr) 









Branches 











; Paternal • 



Total 



bearing 



Seed 



: Seed 



: Percent 



V J V./ v-t -J J 



• (pollen) • 



branches 



viable 



col- 



• ger- 



• ger- 



plants 



: plants 



treated 



seed 



lected 



: minated 



: mination 



Atca 



Cela 



11 



2 



24 



3 



12.5 



Atca 



Atco 



6 



2 



177 



14 



7.9 



Atca 



Atco^ 



6 



1 



45 



3 



6.7 



Atca 



Save 



10 



1 



122 



19 



15. 6 



Atca 



Atga 



12 



6 



387 



45 



11.6 



Atca 



Grbr 



8 



1 



274 



95 



34. 7 



Atca 



Atca 



5 



4 



434 



26 



6.0 



Atca 



Control 



12 



4 



40 



16 



40.0 



'^Species symbols from Plummer and others 1966b. 



Perhaps the most common natural hybrids involving fourwing saltbush are A. 

 canescens x A. con ferti folia and A. eanescens x A. ouneata. The A. canescens x A. 

 confertifolia hybrid closely resembles shadscale in general stature and habit. Spines 

 on the hybrid are more slender, weaker, and much more branched than on the associated 

 shadscale plant (fig. 11). 



This hybrid is similar to fourwing saltbush in the possession of pedicellate 

 bracts and slender branchlets, but it is intermediate between its parents in fruiting 

 bracts, spines, and foliage. For example, the lower half of the bracts is like fourwing 

 saltbush in the possession of four lateral wings, whereas, the upper portion has an ex- 

 panded, foliaceous terminal tooth like shadscale (fig. 7). The A. canescens x A. 

 cuneata combinations are highly variable. Several populations suggest local intro- 

 gression. Individual plants combine parental characteristics in diverse ways. 



Fourwing saltbush has a basic chromosome number of x = 9. Except for the 

 diploid (2n = 18) giant form in the sand dunes of the Little Sahara Recreation Area, 

 Juab County, Utah, this species appears to be uniformly tetraploid (2n = 36) 

 (Stutz and others 1975). 



Distribution and habitat: Fourwing saltbush is one of the most widespread and 

 adaptable of western shrubs. It grows in a variety of soil types from the Great Plains 

 to the coast ranges and from Canada to Mexico at elevations from below sea level to 

 about 2,440 meters (8,000 feet). This species is most suited to deep, well-drained 

 mesas, ridges, slopes, sandy soil, sand dunes, and gravelly washes; but, vigorous 

 plants have been found in heavy clays as well (Plummer and others 1966a) (fig. 13). 

 Fourwing saltbush is frequently found intermixed with black greasewood, shadscale 

 saltbush, basin big sagebrush {Artemisia tridentata subsp. trident ata) , and occasion- 

 ally black sagebrush (-4. nova). Hanson (1962) noted that it tolerates a maximum 

 soluble salt content of about 1,300 p/m. However, we believe there is considerable 

 variation in salt tolerance among ecotypes of A. canescens. 



9 



