Figure 8. — Bigelow sage- 

 brush (k. bigeloviij 

 growing with fourwing 

 saltbush fAtriplex 

 canescensj in a grav- 

 elly draw near Bicknelly 

 Wayne C0.3 Utah. 



A. bigelovii is normally free of insect galls and rust diseases that are common in 

 the other taxa of the section Tridentatae (Beetle 1960). 



Hybridization. --This species has a basic chromosome number of ^=9. Both diploid 

 (2n = 18) and tetraploid (2n = 36) forms are known (Ward 1953; McArthur and Plummer 

 1978) . 



Bigelow sagebrush and basin big sagebrush are often found growing together but are 

 not known to cross or intergrade. 



Distribution and habitat . --Bigelow sagebrush has a more southerly distribution than 

 other sagebrushes. It is one of the most drought-resistant sagebrushes. It occurs over 

 approximately 8,810,000 hectares (34,010 square miles) through western Texas, southern 

 Colorado, New Mexico, Arizona, Utah, Nevada, and California in canyons, gravelly draws 

 and dry flats from 900 to 2,400 meters (3,000 to 7,900 feet) (Ward 1953; Beetle 1960; 

 Kearney and Peebles 1960) (fig. 8). The Bigelow sagebrush type locality is recorded 

 as "rocks and canyons on the Upper Canadian, Texas" (Beetle 1960). 



This species is often found mixed with big sagebrush, black sagebrush, leafless 

 green rabbitbrush {Chrysotharmus nauseosus ssp. junceus) , shadscale [Atriplex oonferti- 

 folia) , and especially matchbrush [Xanthocephalum [Gutierrezia] sarothrae) (Hall and 

 Clements 1923) . 



J/se . --Bigelow sagebrush is palatable to livestock and game in all areas where it 

 occurs. Its twigs are less woody, its odor milder, and its taste is less bitter than 

 most of the big sagebrush complex (Hall and Clements 1923) . 



Artemisia cana Pursh. (silver sagebrush^) 



Silver sagebrush is an erect, freely branched, rounded shrub up to 1.5 meters tall. 

 Older branches have dark-brown, fibrous bark while younger branches are covered with a 

 dense white to yellowish-green tomentum. 



Other common names are white sagebrush, hoary sagebrush, hoary silver sagebrush. 



10 



