Taxonomy
- Kingdom: Plantae
- Clade: Angiosperms → Eudicots → Rosids
- Order: Malpighiales
- Family: Linaceae
- Genus: Hesperolinon
- Species: Hesperolinon breweri (Greene) R.R.Luzier
Common names
- Brewer’s dwarf flax
- Brewer’s hesperolinon
Description
Hesperolinon breweri is an annual herbaceous plant that typically grows 10–30 cm tall. It produces slender, branching stems that are usually glabrous or sparsely hairy. The leaves are narrow, linear to lanceolate, and arranged alternately along the stem. Inflorescences consist of small, bright yellow flowers borne in terminal or axillary racemes. Each flower has five sepals, five petals, and five stamens, typical of the Linaceae family. The fruit is a capsule containing several small seeds.
Distribution and habitat
The species is endemic to the western United States, with its range limited to California. It is most commonly found in the coastal and inland chaparral and foothill regions, particularly on serpentine and other ultramafic soils that are low in nutrients and high in heavy metals. Populations are generally scattered and occur in open, rocky, or sandy microhabitats that receive full sun.
Ecology
H. breweri flowers in late spring to early summer, depending on local climate conditions. Pollination is primarily mediated by native bees and other small insects attracted to the conspicuous yellow flowers. The plant’s seeds are dispersed close to the parent plant, often relying on gravity and occasional water runoff.
Conservation status
Because of its restricted distribution and specialization for serpentine soils, Hesperolinon breweri is considered a species of conservation concern in California. Some populations are threatened by habitat loss due to mining, development, and invasive plant species. It is listed as a California Rare Plant Rank (CRPR) of 4.3 (limited distribution, threatened). Conservation measures focus on habitat protection, monitoring of known populations, and management of invasive species.
Etymology
The genus name Hesperolinon derives from the Greek “hesperos” meaning “western” and “linon” meaning “flax,” reflecting the western North American distribution of the group. The specific epithet breweri honors the 19th‑century American botanist and plant collector William Henry Brewer, who contributed extensively to the flora of California.
References
- Jepson eFlora, University of California, Berkeley. “Hesperolinon breweri.”
- California Native Plant Society (CNPS) Inventory.
- USDA, Natural Resources Conservation Service. “Plant Profile for Hesperolinon breweri.”
Note: All information presented is based on established botanical literature and recognized conservation assessments.
