Tetradymia comosa
Cotton thorn
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Family: Asteraceae · Type: Shrub · Native
Tetradymia comosa (Cotton thorn) is a native California shrub in the Asteraceae family, recognized by pappus absent, replaced by long white hairs.
Cotton thorn is a California native shrub found in southern California coastal regions, Transverse Ranges, and Peninsular Ranges in coastal scrub and chaparral at elevations of 100 to 1,400 meters. Flowering from June to November, this plant produces yellow flowers in clusters of 3 to 6 heads approximately 8 millimeters wide. Growing with stems 30 to 120 centimeters tall that are densely woolly and somewhat spiny, it develops a distinctive tomentose growth habit. Its leaves are narrowly lanceolate, becoming rigid and spine-tipped, generally 2 to 6 centimeters long and covered in soft white hairs. The fruit is approximately 4 millimeters long with long, white, pappus-like hairs.
Identification and appearance
Key characters: 4 sympatric species; diagnostic pappus absent, replaced by long white hairs
Habitat and range
Habitat: Coastal scrub, chaparral
Elevation: 100-1400 m
Outside California: northern Baja California
Bloom period
Tetradymia comosa blooms Jun-Nov.
How to tell it apart
vs Ericameria: Tetradymia has 4-6 bracts in 1-2 rows; Ericameria has many bracts in 5 vertical rows.; vs Artemisia: Tetradymia has rigid spine-tipped branches; Artemisia has soft, non-spiny aromatic foliage.; vs Lycium: Tetradymia has yellow composite flowers; Lycium has tubular purple/greenish flowers with 5 petals.; vs Senecio: Tetradymia has 4-8 flowers per head with woolly appearance; Senecio has more flowers per head and often ray petals.; vs Krascheninnikovia: Tetradymia has yellow composite flowers; Krascheninnikovia has tiny greenish flowers without petals (Chenopodiaceae family).
Frequently asked questions
Is Tetradymia comosa native to California?
Yes. Tetradymia comosa is native to California (recorded as native).
When does Tetradymia comosa bloom?
Tetradymia comosa blooms Jun-Nov.
What plant family does Tetradymia comosa belong to?
Tetradymia comosa is in the Asteraceae family, genus Tetradymia.
What habitat does Tetradymia comosa grow in?
Tetradymia comosa grows in Coastal scrub, chaparral.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · CalPhotos
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.