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

Description

The plant is a small shrub or subshrub up to tall and wide, growing from a caudex 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 An inflorescence is a group or cluster of flowers arranged on a Plant stem, stem that is composed of a main branch or a complicated arrangement of branches. Morphology (biology), Morphologically, it is the modified part of the shoot of sperma ...

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

umbel In botany, an umbel is an inflorescence that consists of a number of short flower stalks (called pedicels) that spread from a common point, somewhat like umbrella ribs. The word was coined in botanical usage in the 1590s, from Latin ''umbella'' "p ...

Varieties

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

endemic Endemism is the state of a species being found 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 found else ...

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

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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