Tetradymia axillaris var. longispina
Catclaw horsebrush
(c) Steve Matson, some rights reserved (CC BY), uploaded by Steve Matson · licence
Family: Asteraceae · Type: Shrub · Native
Tetradymia axillaris var. longispina (Catclaw horsebrush) is a native California shrub in the Asteraceae family, recognized by key difference is tomentose peduncle/involucre and longer hairs.
Catclaw horsebrush is a California native shrub found in southern Sierra Nevada Foothills, eastern Transverse Ranges, northern San Gabriel Mountains, southern Sierra Nevada, and Mojave Desert in desert scrub and woodland habitats at elevations of 1,200 to 2,300 meters. Flowering from April to June, this shrub produces small yellow flowers in clusters with woolly, tomentose flower heads. Growing with stiff, angular branches 30 to 100 centimeters tall, it forms a dense, intricate branching pattern characteristic of desert shrubs. Its leaves are small, narrow, and spine-tipped, giving the plant its distinctive "catclaw" name and providing an effective defense against herbivores. The fruit is covered in long, silky hairs measuring 9 to 11 millimeters in length, which aid in wind dispersal across its arid mountain habitats.
Identification and appearance
Key characters: 8 sympatric species; key difference is tomentose peduncle/involucre and longer hairs
Habitat and range
Habitat: Desert scrub, woodland
Elevation: 1200-2300 m
Outside California: to southwestern Utah
Bloom period
Tetradymia axillaris var. longispina blooms Apr-Jun.
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 axillaris var. longispina native to California?
Yes. Tetradymia axillaris var. longispina is native to California (recorded as native).
When does Tetradymia axillaris var. longispina bloom?
Tetradymia axillaris var. longispina blooms Apr-Jun.
What plant family does Tetradymia axillaris var. longispina belong to?
Tetradymia axillaris var. longispina is in the Asteraceae family, genus Tetradymia.
What habitat does Tetradymia axillaris var. longispina grow in?
Tetradymia axillaris var. longispina grows in Desert scrub, woodland.
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.