Boechera rubicundula
Mount day rockcress, Mount Day Rockcress
Family: Brassicaceae · Type: Perennial · Native
Conservation status: CNPS 1B.1
Boechera rubicundula (Mount day rockcress) is a native California perennial in the Brassicaceae family, recognized by . Key features: horizontal fruits, purple flowers, Bay Area endemic.
Mount day rockcress is a rare (CNPS 1B.1) California native perennial found in the Santa Clara County area of the San Francisco Bay region on rocky slopes at elevations around 1,200 meters. Flowering from April to May, this plant produces purple flowers approximately 6 to 8 millimeters long with petals 2 to 2.5 millimeters wide. Growing with stems 10 to 50 centimeters tall, it emerges from a woody caudex with stems covered in a mix of simple and multi-rayed hairs. Its basal leaves are 4 to 8 millimeters wide with minutely toothed edges, featuring long-stalked, 2 to 5-rayed hairs. The elongated fruits are nearly horizontal, 4 to 8 centimeters long and glabrous, containing 70 to 102 seeds arranged in a single row.
Identification and appearance
Key characters: 2 sympatric species. Key features: horizontal fruits, purple flowers, Bay Area endemic
Habitat and range
Habitat: Rocky slopes
Elevation: +- 1200 m.
Bloom period
Boechera rubicundula blooms Apr-May.
Conservation status
CNPS 1B.1
How to tell it apart
vs Arabis: Boechera pods hang downward or curve and are wider (2mm+); Arabis pods stand rigidly erect and are narrower.; vs Matthiola: Boechera has flattened pods; Matthiola has cylindrical pods and densely hairy gray-green foliage.; vs Streptanthus: Boechera petals narrow gradually without a claw; Streptanthus petals have a distinct narrow claw at base.; vs Penstemon: Boechera has four-petaled flowers and seed pods; Penstemon has tubular five-lobed flowers.; vs Caulanthus: Boechera is perennial with a woody base; Caulanthus is typically annual or biennial without a woody caudex.
Frequently asked questions
Is Boechera rubicundula native to California?
Yes. Boechera rubicundula is native to California (recorded as native).
When does Boechera rubicundula bloom?
Boechera rubicundula blooms Apr-May.
What plant family does Boechera rubicundula belong to?
Boechera rubicundula is in the Brassicaceae family, genus Boechera.
Is Boechera rubicundula rare or endangered?
Boechera rubicundula carries California Rare Plant Rank 1B.1, state rank S1.
What habitat does Boechera rubicundula grow in?
Boechera rubicundula grows in Rocky slopes.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CalPhotos · CDFW CNDDB
Last updated 2026-09-30
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.