Tetradymia argyraea
Striped horsebrush, Striped Horsebrush
(c) Trevor Van Loon, some rights reserved (CC BY) · licence
Family: Asteraceae · Type: Shrub · Native
Conservation status: CNPS 4.3
Tetradymia argyraea (Striped horsebrush) is a native California shrub in the Asteraceae family, recognized by striped stem pattern below spines.
Striped horsebrush is a native shrub found in the southeastern Desert Mountains in blackbush or sagebrush scrub and desert woodland at elevations of 1,200 to 2,230 meters. Flowering from July to October, this plant produces pale yellow flowers in small clusters of 2 to 5 heads about 7 millimeters wide. Growing as a spiny shrub up to 2 meters tall, it develops distinctive stems with alternating glabrous and spiny sections. Its leaves are linear and canescent, with main leaves 1 to 2 centimeters long forming straight or slightly upturned spines, and clustered leaves 3 to 8 millimeters long that are thread-like to club-shaped. The fruit is 2.5 to 3.5 millimeters long with a fine, approximately 8-millimeter pappus of delicate bristles.
Identification and appearance
Key characters: Geographically isolated; diagnostic striped stem pattern below spines
Habitat and range
Habitat: Blackbush or sagebrush scrub, desert woodland
Elevation: 1200-2230 m
Bloom period
Tetradymia argyraea blooms (May)Jul-Oct.
Conservation status
CNPS 4.3
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 argyraea native to California?
Yes. Tetradymia argyraea is native to California (recorded as native).
When does Tetradymia argyraea bloom?
Tetradymia argyraea blooms (May)Jul-Oct.
What plant family does Tetradymia argyraea belong to?
Tetradymia argyraea is in the Asteraceae family, genus Tetradymia.
Is Tetradymia argyraea rare or endangered?
Tetradymia argyraea carries California Rare Plant Rank 4.3, state rank S4.
What habitat does Tetradymia argyraea grow in?
Tetradymia argyraea grows in Blackbush or sagebrush scrub, desert woodland.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · 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.