Descurainia pinnata
Western tansy mustard
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Family: Brassicaceae · Type: Herb · Native
Descurainia pinnata (Western tansy mustard) is a native California herb in the Brassicaceae family, recognized by club-shaped fruits and 2-rowed seeds.
Western tansy mustard is a California native annual herb found in various bioregions in open, dry habitats at low to moderate elevations. Flowering from March to July, this plant produces small yellow flowers about 1 to 3 millimeters long in delicate clusters. Growing 1.3 to 5.7 tall with green or grayish stems that can be simple or branched, it has a distinctive appearance with finely divided leaves. Its leaves are typically 1 to 15 centimeters long, pinnately lobed with 4 to 9 pairs of lateral lobes, each lobe oblanceolate to ovate and sometimes dentate. The fruit is club-shaped, measuring 4 to 13 millimeters long with prominent midveins on each valve.
Identification and appearance
Key characters: 10 sympatric species; club-shaped fruits and 2-rowed seeds help distinguish
Habitat and range
California counties: Kern, San Bernardino, Los Angeles, Fresno, Inyo, Mono, Orange, Riverside, San Diego, San Luis Obispo, Santa Barbara, Imperial, Lassen, Ventura, Plumas, Tehama, Siskiyou, El Dorado, San Joaquin, Humboldt, Modoc, Alameda, Tulare, Placer, Monterey, Nevada, Shasta, Mendocino
How to tell it apart
vs Sisymbrium: Descurainia has soft fuzzy many-branched hairs; Sisymbrium is smooth or has simple unbranched hairs.; vs Lepidium: Descurainia has feathery divided leaves; Lepidium has simple or less-divided leaves and round flat pods.; vs Hirschfeldia: Descurainia has finely divided feathery leaves; Hirschfeldia has lobed but not finely dissected leaves.; vs Brassica: Descurainia has finely divided lacy leaves; Brassica has lobed or simple leaves, not finely dissected.; vs Erodium: Descurainia has four petals and cylindrical pods; Erodium has five petals and long-beaked fruits.
Frequently asked questions
Is Descurainia pinnata native to California?
Yes. Descurainia pinnata is native to California (recorded as native).
Where in California does Descurainia pinnata grow?
Descurainia pinnata occurs in Kern, San Bernardino, Los Angeles, Fresno, Inyo, Mono, Orange, Riverside and other counties.
What plant family does Descurainia pinnata belong to?
Descurainia pinnata is in the Brassicaceae family, genus Descurainia.
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.