Mahonia repens . Native grasses include Stipa viridula and 

 Aaropvron spp. Total cover is about 85 percent. A few plants 

 occur upstream. A complete list of associated taxa includes: 



Achillea millefolium 



Agropyron caninum 



A. smithii (sparse) 



Apocynum androsaemifolium 



Carex torreyi 



Crataegus sp. 



Galium boreale 



Lactuca oblongifolia 



Mahonia repens 



Pinus ponderosa 



Poa pratensis 



Prunus virginiana (saplings) 



Rosa acicularis 



Smilacina stellata 



Symphoricarpos occidentalis 



Stipa viridula 



Thalictrum venulosum 



Vicia americana 



2. Topography: The single study area population occurs on a 

 narrow, north-facing terrace above a small drainage, with 

 slight, 2-5 percent slope. The elevation is app. 1145 m (3760 

 ft), with a few plants at app. 1170 (3840 ft) along the nearby 

 roadside. 



3. Soil relationships: The soil is a brown, sandy loam, with 

 a developed litter layer. 



Population biology and biological interactions 



1. Population size and condition: There were an estimated 

 400 flowering stems within ca. one acre in early July (see 

 following paragraph) . Most of the plants were in an area of 

 ca 30 x 30 m (33 yds) . In late August there were an estimated 

 200 stems, the decrease apparently due to trampling or grazing 

 by cattle. 



2. Reproduction: The few fruits that were observed were 

 found early in the season. On 28 August only one plant was 

 observed with fruit, indicating a season of poor pollination 

 and little seed set. The species spreads extensively by 

 rhizomes so that the flowering stem tally represents ramets 

 rather than genets. The genus in general is adapted for 

 cross-pollination in having stigmatic glands that adhere to 

 insect visitors along with pollen masses (pollinia) for 

 conveyance to other plants (Hitchcock et al. 1984). 



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