Eriogonum ovalifolium Nutt. var. nevadense Gand. 

 Oval-leaved buckwheat 



A. DESCRIPTION 



1. General description: This is a yellow flowered wild 

 buckwheat in the Polygonaceae (slide 9, Appendix E) . The 

 leaves are all basal and covered by white wooly hairs. The 

 flowers are borne in a dense head on a long leafless stalk. 

 The 6 perianth parts are nearly free from each other, with the 

 outer series somewhat broader than the inner. Each flower has 

 9 stamens and 3 styles. 



2. Diagnostic characters: Apparently, the single most 

 important character separating this taxon from other varieties 

 of E. ovalifolium is the yellow flower color (Reveal 1985) . 



It should be noted that in his original description of the 

 species, Nuttall (1834) described the flower color as "bright 

 sulfur yellow." Thus, it is necessary to consider E. 

 ovalifolium var. ovalifolium as the correct name for this 

 taxon, a position which is adopted by Dorn (1988, 1992) but by 

 few others. The likely type for the species came from the Big 

 Hole Valley (Dorn 1988, p. 306). Other synonyms for this 

 taxon are E. o. var. orthocaulon and E. o. var. celsum as used 

 by Hitchcock and Cronquist (1964) and Hitchcock and Cronquist 

 (1973), respectively. They differentiate this taxon primarily 

 on leaf shape and size (the variety of concern, regardless of 

 name, having oblong or obovate leaves 3-6 cm long) , putting 

 less emphasis on flower color. Plants collected by 

 Vanderhorst in 1993 in the Tendoys and on Dutchman Mountain 

 had both bright yellow flowers and relatively large obovate 

 leaves, in contrast to the white (cream-purple) flowered 

 variety with small rhombic to oval leaves. These characters 

 were correlated when both varieties were found growing 

 together close to each other on Dutchman Mountain near Dillon 

 (Vanderhorst, 1994) , but some plants in the Tendoys combined 

 light yellow flowers with leaves of intermediate shape and 

 size (see slide 11 in Appendix E) . 



B. GEOGRAPHIC DISTRIBUTION 



1. Variety Range: For E. ovalifolium var. orthocaulon (a 

 synonym, see above) , Hitchcock and Cronquist (1964) describe 

 the range as "eastern Oregon and northeastern California, 

 east, especially along the Snake River plain, to western 

 Wyoming, Nevada, Utah, and northwestern Colorado, north 

 sporadically to Chelan County, Washington, and southwestern 

 Montana . " 



2. Montana distribution: Beaverhead County. Prior to 1993, 

 two sites were entered in the BCD. In 1993, the species was 

 found to be very common in the vicinity of Horse Prairie, in 

 the foothills of the Pioneer Mountains (Vanderhorst 1994) , and 

 in the Centennial Valley. 



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