Eriogonum giganteum var. formosum
San clemente island buckwheat, San Clemente Island Buckwheat
Photo: parent species Eriogonum giganteum · (c) Adam J. Searcy, some rights reserved (CC BY) · licence
Family: Polygonaceae · Type: Shrub · Native
Conservation status: CNPS 1B.2
Eriogonum giganteum var. formosum (San clemente island buckwheat) is a native California shrub in the Polygonaceae family, recognized by large size and San Clemente Island location.
San clemente island buckwheat is a rare (CNPS 1B.2) California native shrub found on San Clemente Island in southern Channel Islands in gravel habitats at elevations below 300 meters. Flowering from May to September, this plant produces white to cream-colored flowers in large, broad clusters 10 to 50 centimeters wide. Growing 3 to 15 decimeters tall with densely wooly stems that become somewhat smoother with age, the shrub has a robust and spreading growth habit. Its leaves are distinctive, with blades 5 to 8 centimeters long and 1 to 2 centimeters wide, providing a substantial green backdrop to its expansive flower clusters. The plant produces small fruits 3 to 3.5 millimeters long, characteristic of its buckwheat family lineage.
Identification and appearance
Key characters: 20 sympatric species; key features are large size and San Clemente Island location
Habitat and range
Habitat: Gravel
Elevation: < 300 m
California counties: Los Angeles, Santa Barbara, San Diego
Bloom period
Eriogonum giganteum var. formosum blooms May-Sep.
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 giganteum var. formosum native to California?
Yes. Eriogonum giganteum var. formosum is native to California (recorded as native).
When does Eriogonum giganteum var. formosum bloom?
Eriogonum giganteum var. formosum blooms May-Sep.
Where in California does Eriogonum giganteum var. formosum grow?
Eriogonum giganteum var. formosum occurs in Los Angeles, Santa Barbara, San Diego, at elevations of < 300 m.
What plant family does Eriogonum giganteum var. formosum belong to?
Eriogonum giganteum var. formosum is in the Polygonaceae family, genus Eriogonum.
Is Eriogonum giganteum var. formosum rare or endangered?
Eriogonum giganteum var. formosum carries California Rare Plant Rank 1B.2, state rank S3?.
Related species
Other California species in the same genus, family, or bioregion.
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.