Tetradymia is a genus of North American shrubs in the groundsel tribe within the sunflower family. Horsebrush is a common name for plants in this genus. Species 1. \n* Tetradymia argyraea - CA (Riverside + San Bernardino Cos), AZ (Mohave Co), NV (Clark Co) 2. \n* Tetradymia axillaris - CA AZ NV UT 3. \n* Tetradymia canescens - BC WA ID MT WY OR CA NV UT CO AZ NM 4. \n* Tetradymia comosa - CA NV 5. \n* Tetradymia filifolia - NM 6. \n* Tetradymia glabrata - CA NV UT OR ID 7. \n* Tetradymia nuttallii - NV UT CO WY 8. \n* Tetradymia spinosa - CA OR NV ID UT MT WY CO NM 9. \n* Tetradymia stenolepis - CA NV AZ 10. \n* Tetradymia tetrameres - NV CA (Mono Co)formerly included