Arabidopsis thaliana

Mouse-ear cress, thale cress, Thale Cress

Family: Brassicaceae · Type: perennial · Not Native

Mouse-ear cress is a naturalized annual herb found in northwestern California, southern Sacramento Valley, Cascade Range, northern Sierra Nevada, San Francisco Bay Area, southern California Coast, and Warner Range in disturbed ground, sandy areas, flats, and fields at elevations below 1,600 meters. Flowering from February to May, this plant produces small white flowers about 2 to 3.5 millimeters long. Growing with erect, branched stems 5 to 30 centimeters tall, it has spreading simple and forked hairs on lower stems. Its basal leaves are oblanceolate, 0.8 to 3.5 centimeters long, with entire or minutely toothed edges and two- to four-rayed hairs. The slender fruit is 1 to 1.5 centimeters long, with 40 to 70 small oblong seeds.

Habitat: Disturbed ground, sandy areas, flats, fields

Bloom period: Feb-May

Elevation: < 1600 m

Bioregions: NW, ScV, CaR, n SN, SnFrB, SCo, Wrn

California counties: Calaveras, Los Angeles, Placer, El Dorado, Fresno, Kern, Trinity, Shasta, Mariposa, Riverside, Alameda, Amador, Butte, San Luis Obispo, Mendocino, Marin, Humboldt, Stanislaus, Tulare, Tehama, Lake, Modoc, Siskiyou, Del Norte, San Diego, Sacramento, Yolo, Monterey

Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Jepson eFlora, Cal-IPC, and more.