''Eriogonum evanidum'' is a rare species of wild buckwheat known by the common name vanishing wild buckwheat. It is native to southern

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

and

Baja California Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja California ( es, Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 federal entities of Mex ...

, where it has been collected from widely scattered areas. Most historical occurrences are now

extirpated Local extinction, also known as extirpation, refers to a species (or other taxon) of plant or animal that ceases to exist in a chosen geographic area of study, though it still exists elsewhere. Local extinctions are contrasted with global extinct ...

.The Nature Conservancy
/ref> Some sources suggested that it was probably

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

, but living specimens were rediscovered in 2007.

Description

This is an annual herb producing thin, erect stems about 10 or 20 centimeters tall surrounded at the base by small, woolly leaves up to a centimeter long by a centimeter wide. The flowering stem branches from the main stem and is a few centimeters long. It is studded with tiny clumps of yellowish flowers each around a millimeter long.

Taxonomy

The plant was described as a new species by James Reveal in 2004 using specimens that were set aside from a collection of ''Eriogonum foliosum'' on the basis of some morphological characteristics.Reveal, J. L. (2004). New entities in ''Eriogonum'' (Polygonaceae: Eriogonoideae). ''Phytologia''. 86 132. The specimens came from several locations in the southern California mountains, including Bear Valley in the

San Bernardino Mountains The San Bernardino Mountains are a high and rugged mountain range in Southern California in the United States. Situated north and northeast of San Bernardino and spanning two California counties, the range tops out at at San Gorgonio Mountain � ...

and Pine Valley east of

San Diego San Diego ( , ; ) is a city on the Pacific Ocean coast of Southern California located immediately adjacent to the Mexico–United States border. With a 2020 population of 1,386,932, it is the List of United States cities by population, eigh ...

. Herbarium accessions of the plant were made as early as 1893, and most documentation of the species took place between 1920 and 1940.Fraga, N. S., Kempton, E., Gross, L. R., & Bell, D. (2012). Reappearance of the Vanishing Wild Buckwheat: A Status Review of Eriogonum evanidum (Polygonaceae). '' Madroño'', ''59''(3), 150-155. The species was presumed extinct until intensive surveys by the

Rancho Santa Ana Botanic Garden The California Botanic Garden (formerly the Rancho Santa Ana Botanic Garden) is a botanical garden in Claremont, California, in the United States, just south of the San Gabriel foothills. The garden, at , is the largest botanic garden in the sta ...

(RSABG) in late summer and fall of 2007 and 2008 rediscovered the plant. It was found to be extant across its historic range in the United States, but the status of the Baja California population remains unknown.

Etymology

The species was given the name ''Eriogonum evanidum'' and the epithet "vanishing wild buckwheat" because at the time of its description it was presumed to be extinct due to a lack of observations.

Conservation

The primary threats to this species include land development, recreation, and the proliferation of non-native plants. The occurrences of the plant near

Big Bear Lake Big Bear Lake is a reservoir in the San Bernardino Mountains, in San Bernardino County, California, United States. It is a snow and rain fed lake, having no other means of tributaries or mechanical replenishment. At a surface elevation of , it ...

and Baldwin Lake were not located, meaning they were likely extirpated. Surveys at

Warner Springs Warner Springs is set of springs and a small unincorporated community in northern San Diego County, California. Warner Springs is on the Pacific Crest Trail. Geography Warner Springs has a post office and the ZIP code is 92086. It is located n ...

found no suitable habitat.

References

External links

Jepson Manual TreatmentPhoto gallery
evanidum Flora of California Plants described in 2004 {{Polygonaceae-stub