Streptanthus glandulosus subsp. niger

Tiburon jewelflower, Tiburon Jewelflower

Family: Brassicaceae · Type: annual · Native

Conservation status: CNPS 1B.1 · Endangered

Tiburon jewelflower is a rare (CNPS 1B.1) California native annual found in northern Central Coast regions on the Tiburon Peninsula in Marin County, specifically growing on serpentine outcrops in grassland at elevations below 150 meters. Flowering from May to July, this plant produces dark purple flowers approximately 10 to 12 millimeters long with striking dark purple-black sepals. Growing with erect glabrous stems 20 to 110 centimeters tall, it develops an elegant upright structure with wavy flowering axes. Its cauline leaves are glabrous, with upper leaves remaining entire and unserrated, creating a clean, simple foliage profile. The plant produces elongated fruits 3.5 to 6.7 centimeters long that spread at an ascending angle, adding architectural interest to its slender form.

Habitat: Serpentine outcrops in grassland

Bloom period: May-Jul

Elevation: < 150 m

Bioregions: n CCo (Tiburon Peninsula, Marin Co.).

California counties: Marin, San Luis Obispo

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