''Eriogonum sphaerocephalum'' is a species of wild buckwheat known by the common names rock buckwheat and round-headed desert buckwheat. It is native to the western United States.

Habitat

''Eriogonum sphaerocephalum'' can be found primarily east of the crest of the

Cascade Range The Cascade Range or Cascades is a major mountain range of western North America, extending from southern British Columbia through Washington (state), Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as m ...

, in Washington and Oregon to Idaho and from southern Oregon and northern California to northern Nevada. It is a common member of desert, rocky and

sagebrush steppe Sagebrush steppe also known as the sagebrush sea, is a type of shrub-steppe, a plant community characterized by the presence of shrubs, and usually dominated by sagebrush, any of several species in the genus '' Artemisia''.

habitats. It is found over a wide range of elevations, but is most common between .

Description

The plant is a small

shrub A shrub or bush is a small to medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees by their multiple ...

or subshrub up to tall and wide, growing from a

caudex A caudex (: caudices) of a plant is a stem, but the term is also used to mean a rootstock and particularly a basal stem structure from which new growth arises.pages 456 and 695 In the strict sense of the term, meaning a stem, "caudex" is most ...

and producing erect flowering stems. Fresh blooms occur in early summer. The leaves are wooly (typically on the underside), widely lance-shaped to somewhat oval, and long, forming basal rosettes around the caudex and appearing at the end of branches. The

inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...

arises on a stalk and bears many yellow flowers in a head-like cluster or

umbel UMBEL (Upper Mapping and Binding Exchange Layer) is a logically organized knowledge graph of 34,000 concepts and entity types that can be used in information science for relating information from disparate sources to one another. It was retired ...

Varieties

There are several varieties of this species: *''E. s.'' var. ''fasciculifolium'' is

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

to Idaho. *''E. s.'' var. ''halimioides'' is a widespread variety with very pale yellow flowers. *''E. s.'' var. ''sphaerocephalum'' has bright yellow flowers.

References

External links

*
Photo gallery
sphaerocephalum Flora of the Northwestern United States Flora of California Flora of Nevada Flora of the Sierra Nevada (United States) Flora without expected TNC conservation status {{Polygonaceae-stub