Thelypodium howellii subsp. howellii
Howell's thelypodium, Howell's Thelypodium
U.S. Fish & Wildlife Service - Pacific Region's (via Wikimedia Commons) · CC BY
Family: Brassicaceae · Type: Herb · Native
Conservation status: CNPS 1B.2
Thelypodium howellii subsp. howellii (Howell's thelypodium) is a native California herb in the Brassicaceae family, recognized by lyre-shaped leaves and fused filaments.
Howell's thelypodium is a rare (CNPS 1B.2) California native biennial found in the Modoc Plateau in alkaline meadows, flats, and sagebrush scrub at elevations of 1,000 to 1,600 meters. Flowering from May to July, this plant produces lavender to purple flowers 5 to 8 millimeters long with narrow oblanceolate petals. Growing 1 to 9 decimeters tall with simple or branched stems that become glaucous, it features distinctive basal leaves that are lyre-shaped and wither by fruiting time. Its mid-stem leaves are sessile, sagittate, and clasping, with no hairs except on the petiole. The fruit is a cylindric pod 1.5 to 4.5 centimeters long, containing 22 to 40 plump seeds.
Identification and appearance
Key characters: 6 sympatric species; diagnostic lyre-shaped leaves and fused filaments
Habitat and range
Habitat: Alkaline meadows, flats, sagebrush scrub
Elevation: 1000-1600 m
Outside California: to Washington
Bloom period
Thelypodium howellii subsp. howellii blooms May-Jul.
Conservation status
CNPS 1B.2
How to tell it apart
vs Stanleya: Flower stalks barely visible versus quarter-inch-plus dramatic stalks in Stanleya.; vs Caulanthus: Seed pods sit on distinct stalks above flower base versus sitting directly on base.; vs Brassica: Purple to white flowers with stalked pods versus yellow flowers in Brassica.; vs Boechera: Robust plants with relatively large flowers (6-16mm) versus delicate plants with smaller flowers.; vs Noccaea: Tall stems with purple-white flowers versus low rosette plants with tiny white flowers.
Frequently asked questions
Is Thelypodium howellii subsp. howellii native to California?
Yes. Thelypodium howellii subsp. howellii is native to California (recorded as native).
When does Thelypodium howellii subsp. howellii bloom?
Thelypodium howellii subsp. howellii blooms May-Jul.
What plant family does Thelypodium howellii subsp. howellii belong to?
Thelypodium howellii subsp. howellii is in the Brassicaceae family, genus Thelypodium.
Is Thelypodium howellii subsp. howellii rare or endangered?
Thelypodium howellii subsp. howellii carries California Rare Plant Rank 1B.2, state rank S1.
What habitat does Thelypodium howellii subsp. howellii grow in?
Thelypodium howellii subsp. howellii grows in Alkaline meadows, flats, sagebrush scrub.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CalPhotos · CDFW CNDDB
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.