Thysanocarpus rigidus
Rigid fringepod
(c) Jordan Zylstra, some rights reserved (CC BY) · licence
Family: Brassicaceae · Type: Annual · Native
Conservation status: CNPS 1B.2
Thysanocarpus rigidus (Rigid fringepod) is a native California annual in the Brassicaceae family, recognized by branched-from-base habit and purplish coloration.
Rigid fringepod is a rare (CNPS 1B.2) California native annual found in the Peninsular Ranges in southwestern desert areas of Riverside, San Diego, and San Bernardino counties, inhabiting oak and pine woodlands and rocky slopes at elevations of 600 to 2,200 meters. Flowering from February to May, this plant produces delicate white to purplish flowers with distinctive fringed siliques. Growing with branched stems up to 30 centimeters tall, the plant spreads from its base with a glabrous appearance. Its leaves are particularly notable, with basal leaves 2 to 5 centimeters long, oblanceolate to elliptic, featuring wavy or pinnately lobed edges in shades of purple, while upper stem leaves become narrower and more linear. The distinctive fruit is 2.5 to 3.5 millimeters wide, often purplish, with a flat or slightly incurved wing that creates an elegant, delicate silhouette.
Identification and appearance
Key characters: 5 sympatric species; distinguished by branched-from-base habit and purplish coloration
Habitat and range
Habitat: Oak/pine woodland, rocky slopes
Elevation: 600-2200 m
California counties: Los Angeles, San Diego, San Bernardino, Riverside
Outside California: Baja California
Bloom period
Thysanocarpus rigidus blooms Feb-May.
Conservation status
CNPS 1B.2
How to tell it apart
vs Lepidium: Fruits hang downward like lanterns versus standing upright in Lepidium.; vs Athysanus: Fruits have distinctive papery wings with radiating veins versus wingless tiny fruits.; vs Capsella: Fruits are round with lacy wings versus triangular heart-shaped pods.; vs Briza: Mustard with flat winged fruits versus grass with dangling spikelets.; vs Eriogonum: Annual mustard with winged hanging fruits versus buckwheat with ball-like flower clusters.
Frequently asked questions
Is Thysanocarpus rigidus native to California?
Yes. Thysanocarpus rigidus is native to California (recorded as native).
When does Thysanocarpus rigidus bloom?
Thysanocarpus rigidus blooms Feb-May.
Where in California does Thysanocarpus rigidus grow?
Thysanocarpus rigidus occurs in Los Angeles, San Diego, San Bernardino, Riverside, at elevations of 600-2200 m.
What plant family does Thysanocarpus rigidus belong to?
Thysanocarpus rigidus is in the Brassicaceae family, genus Thysanocarpus.
Is Thysanocarpus rigidus rare or endangered?
Thysanocarpus rigidus carries California Rare Plant Rank 1B.2, state rank S2.
Related species
Other California species in the same genus, family, or bioregion.
- Thysanocarpus sp. — Lacepod
- Thysanocarpus conchuliferus — Santa cruz island fringepod
- Thysanocarpus curvipes — Fringe pod
- Thysanocarpus curvipes subsp. amplectens
- Thysanocarpus curvipes subsp. curvipes
- Thysanocarpus curvipes subsp. elegans
- Transberingia bursifolia subsp. virgata — Virgate halimolobos
- Transberingia sp.
- Tropidocarpum californicum — Kings gold
Sources: Jepson eFlora · CNPS Rare Plant Inventory · Index of California Plant Names · 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.