Page author: David Giblin
Arabidopsis thaliana
mouse-ear cress, thalecress

Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east across most of North America.

Habitat: Disturbed areas, particularly near cities and towns.

Flowers: March-May

Origin: Introduced from Eurasia

Growth Duration: Annual

Conservation Status: Not of concern


Annual, the erect stem simple to freely-branched, 1-4 dm. tall, glabrous above but pubescent near the base with simple, spreading hairs.


Leaves many in a basal rosette, oblanceolate, remotely serrulate, 1-4 cm. long, with stiff, simple and forked hairs; cauline leaves alternate, lanceolate, nearly sessile, 5-20 mm. long, the upper ones glabrous.


Inflorescence of open, terminal, many-flowered racemes; pedicels slender, 5-10 mm. long; sepals 4, 1.5 mm. long; petals 4, white, 3 mm. long, narrowly obovate with a wedge-shaped base; stamens 6; style 0.1-0.4 mm. long.


Siliques linear, glabrous, 10-15 mm. long and less than 1 mm. broad.

Accepted Name:
Arabidopsis thaliana (L.) Heynh.
Publication: Fl. Sachsen. 1: 538. 1842.

Synonyms & Misapplications:
(none provided)
Additional Resources:

PNW Herbaria: Specimen records of Arabidopsis thaliana in the Consortium of Pacific Northwest Herbaria database.

WA Flora Checklist: Arabidopsis thaliana checklist entry.

E-Flora BC: Arabidopsis thaliana atlas page.

CalPhotos: Arabidopsis thaliana photos.

USDA Plants: Arabidopsis thaliana information.

40 photographs:
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