Cardamine oligosperma
Bitter cress
(c) Don Loarie, some rights reserved (CC BY) · licence
Family: Brassicaceae · Type: Herb · Native
Cardamine oligosperma (Bitter cress) is a native California herb in the Brassicaceae family, recognized by native annual with basal rosette diagnostic.
Bitter cress is a native annual herb found in California Floristic Province and Western and Inner Coast Ranges in wet meadows, shady banks, and damp areas at elevations of 50 to 3,300 meters. Flowering from March to July, this plant produces small white flowers about 2.5 to 3.5 millimeters long in elongated clusters. Growing with erect or ascending stems 8 to 30 centimeters tall, it emerges with multiple stems from a single base and features a taproot. Its leaves are pinnately compound with 5 to 9 leaflets, the terminal leaflet 4 to 15 millimeters long and round or ovate, often larger than the lateral leaflets. The fruits are slender, ascending pods 16 to 28 millimeters long containing 16 to 32 small oblong seeds.
Identification and appearance
Key characters: 10 sympatric species; native annual with basal rosette diagnostic
Habitat and range
Habitat: Wet meadows, shady banks, damp areas
Elevation: 50-3300 m
California counties: Contra Costa, Alameda, Butte, Humboldt, Lake, Los Angeles, Madera, Mendocino, Monterey, San Francisco, San Luis Obispo, San Mateo, Santa Barbara, Santa Clara, Shasta, Solano, Tehama, Trinity, Ventura, Sacramento, Sonoma, San Bernardino, Fresno, Nevada, Placer, San Diego, Sutter, Yuba, Tulare, San Benito, El Dorado, Amador, Inyo, Napa, Calaveras, Marin, Tuolumne, Santa Cruz, Plumas, Mariposa, Stanislaus, Del Norte, Glenn, Siskiyou, Colusa, Lassen, Yolo, San Joaquin, Merced
Outside California: to British Columbia, Montana, Colorado, Baja California
Bloom period
Cardamine oligosperma blooms Mar-Jul.
How to tell it apart
vs Raphanus: Cardamine has narrow pencil-like pods with many seeds; Raphanus has thick beaked pods that break into segments.; vs Nasturtium: Cardamine grows on moist land in shade; Nasturtium grows in or at the edge of water in sun.; vs Viola: Cardamine has four petals and thin seed pods; Viola has five petals and a capsule that splits into three parts.; vs Vancouveria: Cardamine has four-petaled flowers and seed pods; Vancouveria has six-petaled flowers and follicles.; vs Lepidium: Cardamine has narrow pods with many seeds; Lepidium has flattened round pods with only 2 seeds.
Frequently asked questions
Is Cardamine oligosperma native to California?
Yes. Cardamine oligosperma is native to California (recorded as native).
When does Cardamine oligosperma bloom?
Cardamine oligosperma blooms Mar-Jul.
Where in California does Cardamine oligosperma grow?
Cardamine oligosperma occurs in Contra Costa, Alameda, Butte, Humboldt, Lake, Los Angeles, Madera, Mendocino and other counties, at elevations of 50-3300 m.
What plant family does Cardamine oligosperma belong to?
Cardamine oligosperma is in the Brassicaceae family, genus Cardamine.
What habitat does Cardamine oligosperma grow in?
Cardamine oligosperma grows in Wet meadows, shady banks, damp areas.
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.