Figure 20. --Mat saLtbush and Castle Va,lley clover saltbush growing on outcropping of 

 Mancos sha.le in a. jimiper-pinyon-grass type in northeastern Sevier County^, Utah. 



The evergreen sessile leaves are opposite on the lower parts of the stems and 

 alternate above. The blades are densely scurfy and measure 7 to 18 mm wide. 



Bushes are dioecious or rarely monoecious. The yellow to light -brown staminate 

 flowers are borne in glomerules 3 to 6 mm wide on nearly naked spikes. The pairs of 

 fruiting bracts that enclose the pistils of the female flowers are sessile or 

 subsessile, 3 to 5 mm long, 4 to 6 mm wide, united along seven-tenths of their length 

 and usually densely tuberculate on the lower one-third (fig. 7). 



Mat saltbush flowers from April to June and the fruit ripens 5 to 6 weeks later. 

 There are about 100,900 cleaned utricles of mat saltbush per pound (223/g) . 



Hybridization: Viable seed has been obtained by artificially pollinating fourwing 

 saltbush with pollen from mat saltbush (table 1). Natural hybrids between this species 

 and A. gardneri and A. oonfertifolia have been found (Hanson 1962) . Mat saltbush is 

 tetraploid (2n = 36) (H. C. Stutz and C. L. Pope, personal communication). 



Distribution and habitat: Mat saltbush is distributed mainly on soils derived 

 from the Mancos Shale Formation in eastern Utah (fig. 20), western Colorado, and 

 northwestern New Mexico at elevations from 1,220 to 2,130 meters (4,000 to 7,000 feet). 

 It tolerates up to 13,000 p/m soluble salts and is often the only perennial plant 

 present where such high concentrations of salt occur (Hanson 1962) . Mat saltbush is 

 probably the most halophytic shrub in the genus, but it is frequently found in areas 

 where the salt concentration is not so high. In these areas, it may be associated with 

 shrubs such as winterfat, cuneate saltbush, shadscale saltbush, fourwing saltbush, black 

 greasewood, bud sagebrush, and gray molly (Koohia americana subsp. vestita) . We have 

 successfully transplanted young plants into a former greasewood type in the Great Basin. 



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