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. Ecology 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. Monophagous Lepidoptera on wild buckwheat include: Apodemia mormo (Mormon metalmark) – feeds exclusively on Eriogonum Apodemia mormo langei (Lange's metalmark) – only known from Eriogonum nudum ssp. auriculatum Chionodes dammersi – feeds exclusively on Eriogonum Chionodes luteogeminatus – only known from Eriogonum niveum Euphilotes enoptes smithi (Smith's blue butterfly) – only known from Eriogonum latifolium and Eriogonum parvifolium Euphilotes battoides allyni (El Segundo blue butterfly) - only known from Eriogonum parvifolium Additionally, bees of the sagebrush steppe rely on the nectar of desert buckwheats, and birds and rodents eat the seeds. Uses Some varieties of eriogonum, such as California buckwheat were and still are used as medicinal and food crops by Native American tribes. Selected species Eriogonum abertianum – Abert's buckwheat Eriogonum alatum – winged buckwheat Eriogonum alexanderae Eriogonum aliquantum – Cimarron buckwheat Eriogonum alpinum – trinity buckwheat Eriogonum ampullaceum – mono buckwheat Eriogonum androsaceum – rock-jasmine buckwheat Eriogonum angulosum – anglestem buckwheat Eriogonum apiculatum – San Jacinto buckwheat Eriogonum apricum – Ione buckwheat Eriogonum arborescens – Santa