Eriogonum nudum var. regirivum
Kings river buckwheat, Kings River Buckwheat
Photo: parent species Eriogonum nudum · no rights reserved · CC0
Family: Polygonaceae · Type: Subshrub · Native
Conservation status: CNPS 1B.2
Eriogonum nudum var. regirivum (Kings river buckwheat) is a native California subshrub in the Polygonaceae family, recognized by Kings River (Pine Flat, Fresno Co.) endemic; tomentose stems, solitary involucre, tiny (1.5–2 mm) flowers.
Kings river buckwheat is a rare (CNPS 1B.2) California native perennial found in southern Sierra Nevada Foothills near Kings River in Fresno County, growing in gravel habitats at elevations of 200 to 600 meters. Flowering from August to November, this plant produces white flowers in compact clusters with hairy perianths. Growing 5 to 10 decimeters tall with tomentose stems measuring 1 to 3 decimeters long, it develops an expansive branching structure up to 100 centimeters wide. Its leaves are primarily basal, with fuzzy blades 2 to 3.5 centimeters long and 1.5 to 2.5 centimeters wide, covered in soft tomentose hair. The plant's involucres are small, measuring 3 to 4 millimeters and also covered in tomentose hair.
Identification and appearance
Key characters: Kings River (Pine Flat, Fresno Co.) endemic; tomentose stems, solitary involucre, tiny (1.5–2 mm) flowers
Habitat and range
Habitat: Gravel
Elevation: 200-600 m
California counties: Fresno, Mariposa
Bloom period
Eriogonum nudum var. regirivum blooms Aug-Nov.
Conservation status
CNPS 1B.2
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 nudum var. regirivum native to California?
Yes. Eriogonum nudum var. regirivum is native to California (recorded as native).
When does Eriogonum nudum var. regirivum bloom?
Eriogonum nudum var. regirivum blooms Aug-Nov.
Where in California does Eriogonum nudum var. regirivum grow?
Eriogonum nudum var. regirivum occurs in Fresno, Mariposa, at elevations of 200-600 m.
What plant family does Eriogonum nudum var. regirivum belong to?
Eriogonum nudum var. regirivum is in the Polygonaceae family, genus Eriogonum.
Is Eriogonum nudum var. regirivum rare or endangered?
Eriogonum nudum var. regirivum carries California Rare Plant Rank 1B.2, state rank S2.
Related species
Other California species in the same genus, family, or bioregion.
- Eriogonum nudum var. scapigerum — Sierran crest wild buckwheat
- Eriogonum nudum var. westonii — Weston's wild buckwheat
- Eriogonum nummulare — Money wild buckwheat
- Eriogonum nutans — Dugway buckwheat
- Eriogonum nutans var. glabratum — Deeth wild buckwheat
- Eriogonum nutans var. nutans — Dugway wild buckwheat
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.