Hesperolinon congestum
Marin western flax, Marin Western Flax
(c) Michael Warner, some rights reserved (CC BY) · licence
Family: Linaceae · Type: Herb · Native
Conservation status: CNPS 1B.1 · Threatened
Hesperolinon congestum (Marin western flax) is a native California herb in the Linaceae family, recognized by restricted low elevation range and pink flowers with hairy sepals.
Marin western flax is a rare (CNPS 1B.1) California native annual found in northern Coast Ranges and San Francisco Bay Area in serpentine grasslands at elevations below 200 meters. Flowering from April to August, this delicate plant produces pink to rose flowers with distinctive rose to purple anthers in small dense clusters. Growing with slender stems 5 to 15 centimeters tall, it develops linear alternate leaves with well-developed red-exuding stipule glands. Its leaves are nearly hairless and characterized by their narrow, linear shape with conspicuous red glandular stipules. The small flowers feature hairy sepals 3 to 4 millimeters long and petals 3 to 8 millimeters in soft pink to rose tones.
Identification and appearance
Key characters: 2 sympatric species; restricted low elevation range and pink flowers with hairy sepals
Habitat and range
Habitat: Serpentine, grassland
Elevation: < 200 m
California counties: San Mateo, Marin, San Francisco, Colusa
Bloom period
Hesperolinon congestum blooms Apr-Aug.
Conservation status
CNPS 1B.1 · Threatened
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 congestum native to California?
Yes. Hesperolinon congestum is native to California (recorded as native).
When does Hesperolinon congestum bloom?
Hesperolinon congestum blooms Apr-Aug.
Where in California does Hesperolinon congestum grow?
Hesperolinon congestum occurs in San Mateo, Marin, San Francisco, Colusa, at elevations of < 200 m.
What plant family does Hesperolinon congestum belong to?
Hesperolinon congestum is in the Linaceae family, genus Hesperolinon.
Is Hesperolinon congestum rare or endangered?
Hesperolinon congestum carries California Rare Plant Rank 1B.1, state rank S1.
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.