Tetradymia stenolepis
Mojave cottonthorn
(c) Steve Matson, some rights reserved (CC BY) · licence
Family: Asteraceae · Type: Shrub · Native
Tetradymia stenolepis (Mojave cottonthorn) is a native California shrub in the Asteraceae family, recognized by straight spines and large clustered leaves.
Mojave cottonthorn is a native shrub found in southern Sierra Nevada foothills, Tehachapi, eastern Western Transverse Ranges, northern San Gabriel Mountains, Southeastern Sierra Nevada, and Mojave Desert in desert woodland and creosote-bush scrub at elevations of 600 to 1,700 meters. Flowering from June to November, this plant produces pale yellow flowers in heads 4 to 7, with each flower head approximately 8 to 10 millimeters long. Growing up to 1.2 meters tall with distinctive spiny branches and unevenly tomentose stems that become nearly glabrous in stripes below the spines, it forms a dense, intricate shrub. Its leaves include main leaves 2 to 3 centimeters long that form straight spines, and smaller clustered leaves 10 to 30 millimeters long that are approximately oblanceolate and covered in tomentose or silvery hairs. The fruit is 5 to 8 millimeters long with many fine pappus bristles 9 to 12 millimeters in length.
Identification and appearance
Key characters: 8 sympatric species; key features are straight spines and large clustered leaves
Habitat and range
Habitat: Desert woodland, creosote-bush or saltbush scrub
Elevation: 600-1700 m
Outside California: southern Nevada
Bloom period
Tetradymia stenolepis 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 stenolepis native to California?
Yes. Tetradymia stenolepis is native to California (recorded as native).
When does Tetradymia stenolepis bloom?
Tetradymia stenolepis blooms Jun- Nov.
What plant family does Tetradymia stenolepis belong to?
Tetradymia stenolepis is in the Asteraceae family, genus Tetradymia.
What habitat does Tetradymia stenolepis grow in?
Tetradymia stenolepis grows in Desert woodland, creosote-bush or saltbush scrub.
Related species
Other California species in the same genus, family, or bioregion.
- Tetradymia tetrameres — Dune horsebrush
- Tetradymia argyraea — Striped horsebrush
- Tetradymia axillaris — Catclaw horsebrush
- Tetradymia axillaris var. axillaris — Catclaw horsebrush
- Tetradymia axillaris var. longispina — Catclaw horsebrush
- Tetradymia canescens — Gray horsebrush
- Tetraneuris acaulis var. arizonica — Arizona four nerve daisy
- Tetraneuris sp.
- Thelesperma megapotamicum — Rayless greenthread
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.