Eriogonum umbellatum var. humistratum
Mount eddy buckwheat, Mount Eddy Buckwheat
Photo: parent species Eriogonum umbellatum · Photo by Chez Brungraber
Family: Polygonaceae · Type: Subshrub · Native
Conservation status: CNPS 4.3
Eriogonum umbellatum var. humistratum (Mount eddy buckwheat) is a native California subshrub in the Polygonaceae family, recognized by high-elevation serpentine habitat distinctive.
Mount eddy buckwheat is a rare California native perennial ranked 4.3 by CNPS, found in the Klamath Ranges and northern California Ranges, specifically in the White Mountains, Mount Eddy, Scott Mountains, and Mount Shasta regions on serpentine terrain at elevations of 1,700 to 2,800 meters. Flowering from June to September, this plant produces distinctive yellow flowers 3 to 6 millimeters long in delicate umbels. Growing as a low mat 1 to 3 meters in diameter with hairy stems 5 to 15 centimeters tall, it forms a compact ground-hugging structure. Its leaves are small, tomentose blades 5 to 15 millimeters long and wide, creating a dense silvery-green ground cover. The plant's compact mat form and silvery foliage make it particularly well-adapted to harsh, rocky serpentine environments.
Identification and appearance
Key characters: 44 sympatric species; high-elevation serpentine habitat distinctive
Habitat and range
Habitat: Serpentine
Elevation: 1700-2800 m
California counties: Siskiyou, Trinity, Shasta, Tehama
Bloom period
Eriogonum umbellatum var. humistratum blooms Jun-Sep.
Conservation status
CNPS 4.3
How to tell it apart
vs Adenostoma: Eriogonum has flowers in cup-like involucres; Adenostoma has tiny white rose-family flowers in spikes.; vs Salvia: Eriogonum has six similar perianth parts; Salvia has two-lipped tubular flowers.; vs Fagopyrum: Eriogonum has flowers in involucred clusters; Fagopyrum has loose branching sprays without involucres.; vs Artemisia: Eriogonum has cup-surrounded flower clusters; Artemisia has tiny inconspicuous heads in drooping sprays.; vs Chorizanthe: Eriogonum has multiple flowers per involucre; Chorizanthe has one flower per involucre with spiny teeth.
Frequently asked questions
Is Eriogonum umbellatum var. humistratum native to California?
Yes. Eriogonum umbellatum var. humistratum is native to California (recorded as native).
When does Eriogonum umbellatum var. humistratum bloom?
Eriogonum umbellatum var. humistratum blooms Jun-Sep.
Where in California does Eriogonum umbellatum var. humistratum grow?
Eriogonum umbellatum var. humistratum occurs in Siskiyou, Trinity, Shasta, Tehama, at elevations of 1700-2800 m.
What plant family does Eriogonum umbellatum var. humistratum belong to?
Eriogonum umbellatum var. humistratum is in the Polygonaceae family, genus Eriogonum.
Is Eriogonum umbellatum var. humistratum rare or endangered?
Eriogonum umbellatum var. humistratum carries California Rare Plant Rank 4.3, state rank S4.
Related species
Other California species in the same genus, family, or bioregion.
- Eriogonum umbellatum var. juniporinum — Juniper sulphur-flowered buckwheat
- Eriogonum umbellatum var. lautum — Scott valley buckwheat
- Eriogonum umbellatum var. minus — Alpine sulphur-flowered buckwheat
- Eriogonum umbellatum var. modocense — Modoc sulphur flower
- Eriogonum umbellatum var. munzii — Munz's sulphur flower
- Eriogonum umbellatum var. nelsoniorum — Nelsons' sulphur flower
Sources: Jepson eFlora · CNPS Rare Plant Inventory · Index of California Plant Names · CalPhotos · CDFW CNDDB
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.