Hesperolinon bicarpellatum
Two-carpellate western flax
(c) Trevor Van Loon, some rights reserved (CC BY) · licence
Family: Linaceae · Type: Herb · Native
Conservation status: CNPS 1B.2
Hesperolinon bicarpellatum (Two-carpellate western flax) is a native California herb in the Linaceae family, recognized by unique 2-carpellate ovary with 4 chambers.
Two-carpellate western flax is a rare (CNPS 1B.2) California native annual found in southern North Coast Ranges Interior in serpentine chaparral at elevations of 60 to 1,000 meters. Flowering from May to July, this plant produces yellow flowers 2 to 4 millimeters long with delicate petals. Growing 10 to 30 centimeters tall with an upright form, it has slender stems that are mostly smooth except just above the leaf nodes. Its leaves are thread-like and linear, growing alternately along the stem and remaining flat without clasping. The plant's distinctive yellow stamens are 3 to 5 millimeters long, matching its yellow styles which emerge from its 4-chambered ovary.
Identification and appearance
Key characters: 5 sympatric species; unique 2-carpellate ovary with 4 chambers
Habitat and range
Habitat: Serpentine, chaparral
Elevation: 60-1000 m
Bloom period
Hesperolinon bicarpellatum blooms May-Jul.
Conservation status
CNPS 1B.2
How to tell it apart
vs Linum: Hesperolinon has 2-3 styles and whorled basal leaves; Linum has 5 styles and alternate leaves.; vs Gayophytum: Hesperolinon has whorled leaves and 2-3 styles; Gayophytum has alternate leaves and 4-parted flowers.; vs Eremogone: Hesperolinon has 2-3 styles; Eremogone has 3 styles and opposite leaves throughout.; vs Nemacladus: Hesperolinon has regular radial flowers; Nemacladus has strongly bilateral flowers.; vs Sclerolinon: Hesperolinon has 3 styles and stipule glands present; Sclerolinon has 2 club-shaped styles and no glands.
Frequently asked questions
Is Hesperolinon bicarpellatum native to California?
Yes. Hesperolinon bicarpellatum is native to California (recorded as native).
When does Hesperolinon bicarpellatum bloom?
Hesperolinon bicarpellatum blooms May-Jul.
What plant family does Hesperolinon bicarpellatum belong to?
Hesperolinon bicarpellatum is in the Linaceae family, genus Hesperolinon.
Is Hesperolinon bicarpellatum rare or endangered?
Hesperolinon bicarpellatum carries California Rare Plant Rank 1B.2, state rank S2.
What habitat does Hesperolinon bicarpellatum grow in?
Hesperolinon bicarpellatum grows in Serpentine, chaparral.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · 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.