Great Basin Naturalist


Ecological and community relationships of 10 different plant communities in the Uinta Basin, Utah, where Eriogonum corymbosum was found to grow were studied and described. Each community was sampled to determine the amount of ground cover, percent composition, frequency, and density of participating species. Physical site factors, viz., soil texture, total soluble salts, pH, cation exchange capacity, and amounts of calcium, magnesium, potassium, and sodium were determined. The 10 communities were compared to determine the degree of similarity between them. Correlations between individual plant species and measurable characteristics of the community were attempted. Evidence is presented that the distributional patterns of some species are related to these measured characteristics. Eriogonum corymbosum, Chenopodium leptophyllum, Atriplex confertifolia, Stipa comata, Artemisia tridentata, and Agropyron smithii showed correlation to both vegetational and edaphic factors of the community.

Total vegetative cover increased from desert to mountain in the Uinta Basin. As the vegetative cover increased, soil depth also increased. Eriogonum corymbosum decreased in importance in the higher elevation communities.

Eriogonum corymbosum was studied taxonomically, which demonstrated the presence of a previously undescribed variety. It is suggested that E. corymbosum var. corymbosum, found generally in the desert areas of the basin, is composed of a series of ecotypes that inhabit shallow soils and prefer communities that show high degrees of disturbance, little competition, fairly high levels of soluble salts in the soil, and are found at elevations below 5500 feet. Eriogonum corymbosum var. erectum, on the other hand, does best in communities above 6000 feet that show less disturbance than the desert areas, have deeper soils, and low levels of soluble salts.