Nevada City buckwheat

Description

Eriogonum prattenianum is a species of wild buckwheat known by the common name Nevada City buckwheat. Eriogonum prattenianum is a small shrub growing up to about half a meter tall when erect in form or growing in a clump or mat lined with oval-shaped woolly leaves. The inflorescence arises on a slender scape and bears a rounded cluster of yellow flowers. Eriogonum prattenianum is endemic to California, where it can be found in many scattered disjunct populations in the Sierra Nevada and its foothills. There are two varieties of this species. The more common var. prattenianum occurs in scattered populations in the mountains and foothills, while the uncommon var. avium is limited to granite outcrops in the Sierra Nevada slopes of Madera and Fresno Counties. The latter is generally a smaller plant than the former. Eriogonum is a genus of flowering plants in the family Polygonaceae. The genus is found in North America and is known as wild buckwheat. This is a highly species-rich genus, and indications are that active speciation is continuing. It includes some common wildflowers such as the California buckwheat (Eriogonum fasciculatum). The genus derived its name from the Greek word erion meaning 'wool' and gonu meaning 'knee or joint'. The author of the genus, Michaux, explained the name as describing the first named species of the genus (E. tomentosum) as a wooly plant with sharply bent stems ("planta lanata, geniculata"). Despite sharing the common name "buckwheat", Eriogonum is part of a different genus than the cultivated European buckwheat and than other plant species also called wild buckwheat. It came into the news in 2005 when the Mount Diablo buckwheat (Eriogonum truncatum, believed to be extinct) was rediscovered. Eriogonum species are used as food plants by the larvae of some Lepidoptera (butterflies and moths). An example of a butterfly that uses this plant for food is the Lycaena heteronea. Several of these are monophagous, meaning their caterpillars only feed on this genus, sometimes just on a single taxon of Eriogonum. Wild buckwheat flowers are also an important source of food for these and other Lepidoptera. In some cases, the relationship is so close that Eriogonum and dependent Lepidoptera are in danger of coextinction. Some varieties of eriogonum, such as California buckwheat were and still are used as medicinal and food crops by Native American tribes.