Pentachaeta exilis subsp. aeolica
San benito pentachaeta, San Benito Pentachaeta
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Family: Asteraceae · Type: Herb · Native
Conservation status: CNPS 1B.2
Pentachaeta exilis subsp. aeolica (San benito pentachaeta) is a native California herb in the Asteraceae family, recognized by consistently radiate heads with white rays.
San benito pentachaeta is a rare (CNPS 1B.2) California native annual found in San Francisco Bay and south-central coastal ranges in grassland and woodland habitats at elevations below 750 meters. Flowering from March to May, this plant produces distinctive white ray flowers and yellow disk flowers in radiate heads. Growing delicately with slender stems to approximately 30 centimeters tall, the plant forms an open, spreading growth habit. Its leaves are narrow and lance-shaped, typically green and relatively small, arranged alternately along the stem. The fruit develops as small, dry achenes characteristic of the daisy family.
Identification and appearance
Key characters: 5 sympatric species; key feature is consistently radiate heads with white rays
Habitat and range
Habitat: Grassland, woodland
Elevation: < 750 m
Bloom period
Pentachaeta exilis subsp. aeolica blooms Mar-May.
Conservation status
CNPS 1B.2
How to tell it apart
vs Lasthenia: Pentachaeta has only 1-5 female flowers per head; Lasthenia has many more female flowers.; vs Thymophylla: Pentachaeta is non-glandular and unscented; Thymophylla is strongly aromatic with glands.; vs Eriophyllum: Pentachaeta has thread-like delicate stems; Eriophyllum has sturdier stems and woolly coating.; vs Bebbia: Pentachaeta is tiny delicate annual; Bebbia is woody shrub with nearly leafless stems.; vs Hazardia: Pentachaeta is thread-like delicate annual; Hazardia is woody leafy shrub.
Frequently asked questions
Is Pentachaeta exilis subsp. aeolica native to California?
Yes. Pentachaeta exilis subsp. aeolica is native to California (recorded as native).
When does Pentachaeta exilis subsp. aeolica bloom?
Pentachaeta exilis subsp. aeolica blooms Mar-May.
What plant family does Pentachaeta exilis subsp. aeolica belong to?
Pentachaeta exilis subsp. aeolica is in the Asteraceae family, genus Pentachaeta.
Is Pentachaeta exilis subsp. aeolica rare or endangered?
Pentachaeta exilis subsp. aeolica carries California Rare Plant Rank 1B.2, state rank S2.
What habitat does Pentachaeta exilis subsp. aeolica grow in?
Pentachaeta exilis subsp. aeolica grows in Grassland, woodland.
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.