various shrubs and other species, in aggregate forming less 

 than 10 percent cover. Typical shrubs are Rhus trilobata , and 

 low forms of Amelanchier alnifolia and Prunus virginiana . 

 Clumps of Agropyron spicatum and Andropogon scoparius are 

 present at one site, Oryzopsis hymenoides at another. 



A complete list of associated taxa is: 



Agropyron spicatum 



Allium textile 



Amelanchier alnifolia 



Andropogon scoparius 



Astragalus missouriensis 



Chaenactis douglasii 



Commandra umbellata 



Gaura coccinea 



Heterotheca villosa 



Ipomopsis congesta 



Lesguerella alpina 



Lupinus pusillus 



Oryzopsis hymenoides 



Petalostemon candidum 



Prunus virginiana 



Psoralea esculenta 



Rhus trilobata 



Rumex venosus 



Solidago missouriensis 



Stephanomeria runcinata 



Tradescantia occidentalis 



Yucca glauca 



2. Topography: The species occurs on steep, southerly slopes 

 at mid and lower slope positions along ridges within valley 

 drainages. Elevation at one site is from app. 1085-1091 m 

 (3560 to 3580 ft) , and from 1134-1149 m (3770-3720 ft) at the 

 other site. 



3. Soil relationships: The soil is a loose, unstable, brown, 

 gravelly sand. Outcrops of decaying soft sandstone are 

 present on one site. At another, the sandy soil may overly 

 clay or shale soils or bedrock. Typically the upper soil is 

 loose and shifting, and may be bounded above and below by clay 

 or shale bedrock. One subpopulation occurs along a sandy 

 slump just above a roadcut. 



E. Species biology, population biology and biological interactions 



1. Population size and condition: Populations were app. 20 

 and 40 plants, both occupying an area of less than an acre. 



2. Reproduction: Outcrossing. 



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