Eriogonum umbellatum var. polyanthum
American river sulphur flower, American River Sulphur Flower
Photo: parent species Eriogonum umbellatum · Photo by Chez Brungraber
Family: Polygonaceae · Type: Shrub · Native
Eriogonum umbellatum var. polyanthum (American river sulphur flower) is a native California shrub in the Polygonaceae family, recognized by large shrub habit and compound inflorescence.
American river sulphur flower is a California native shrub found in the Klamath Ranges, northern Sierra Nevada and Cascade Ranges, and Modoc Plateau in serpentine habitats at elevations of 800 to 1,500 meters. Flowering from June to September, this plant produces distinctive yellow flowers in compact umbellate clusters. Growing 4 to 10 decimeters tall with a spread of 5 to 10 decimeters, it develops hairy stems up to 2 decimeters long. Its leaves are small and compact, measuring 1 to 3 centimeters long and 0.3 to 1 centimeter wide, with a tomentose (woolly) undersurface and lighter green upper surface. The shrub's delicate yellow flowers and woolly textured leaves make it a distinctive component of serpentine landscapes.
Identification and appearance
Key characters: 81 sympatric species; distinguished by large shrub habit and compound inflorescence
Habitat and range
Habitat: Serpentine(?)
Elevation: 800-1500 m
California counties: Shasta, Lassen, Plumas, Modoc, Alpine, Siskiyou, Nevada, Humboldt, Trinity, Amador, Sierra, Del Norte, El Dorado, Tulare, Kern, Butte, Tuolumne, Mendocino, Fresno, Marin
Bloom period
Eriogonum umbellatum var. polyanthum blooms Jun-Sep.
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. polyanthum native to California?
Yes. Eriogonum umbellatum var. polyanthum is native to California (recorded as native).
When does Eriogonum umbellatum var. polyanthum bloom?
Eriogonum umbellatum var. polyanthum blooms Jun-Sep.
Where in California does Eriogonum umbellatum var. polyanthum grow?
Eriogonum umbellatum var. polyanthum occurs in Shasta, Lassen, Plumas, Modoc, Alpine, Siskiyou, Nevada, Humboldt and other counties, at elevations of 800-1500 m.
What plant family does Eriogonum umbellatum var. polyanthum belong to?
Eriogonum umbellatum var. polyanthum is in the Polygonaceae family, genus Eriogonum.
What habitat does Eriogonum umbellatum var. polyanthum grow in?
Eriogonum umbellatum var. polyanthum grows in Serpentine(?).
Related species
Other California species in the same genus, family, or bioregion.
- Eriogonum umbellatum var. smallianum — Small's sulphur flower
- Eriogonum umbellatum var. speciosum — Beautiful sulphur flower
- Eriogonum umbellatum var. subaridum — Ferris' sulphur flower
- Eriogonum umbellatum var. torreyanum — Donner pass buckwheat
- Eriogonum umbellatum var. versicolor — Panamint sulphur flower
- Eriogonum ursinum — Bear buckwheat
Sources: Jepson eFlora · Index of California Plant Names · CalPhotos
Last updated 2026-09-30
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.