Poteridium annuum
Western burnet
(c) Sam Kieschnick, some rights reserved (CC BY) · licence
Family: Rosaceae · Type: Herb · Native
Poteridium annuum (Western burnet) is a native California herb in the Rosaceae family, recognized by Only Poteridium species in CA, distinct from related genus Poterium by annual habit and fruit characteristics.
Western burnet is a native annual herb found in the Klamath Ranges, northern California Ranges, northern Sierra Nevada, northern Coast Ranges, Peninsular Ranges, and Modoc Plateau in open, especially disturbed areas at elevations of 225 to 1,890 meters. Flowering from April to July, this plant produces small clustered flowers in dense cylindric-ovoid spikes 5 to 35 millimeters long. Growing with ascending to erect stems 10 to 70 centimeters tall, it develops a taproot and maintains an open, slender structure. Its alternate leaves are oddly pinnately compound with 4 to 7 leaflets on each side, each leaflet approximately obovate-elliptic and 5 to 20 millimeters long with linear lobes less than two-thirds the way to the midvein. The fruit is a hard, 4-angled hypanthium 2 to 4 millimeters long that wraps around a small achene with slightly wrinkled surfaces.
Identification and appearance
Key characters: Only Poteridium species in CA, distinct from related genus Poterium by annual habit and fruit characteristics
Habitat and range
Habitat: Open, especially disturbed areas
Elevation: 225-1890 m
California counties: Modoc, Sierra, Nevada, Plumas, Butte, Tehama, Lassen, Siskiyou, Shasta, Santa Barbara, San Bernardino, Sacramento, Santa Cruz, Ventura, Placer, San Diego, Calaveras
Outside California: to British Columbia, Montana
Bloom period
Poteridium annuum blooms Apr-Jul.
How to tell it apart
vs Aphanes: Poteridium has pinnate compound leaves; Aphanes has palm-lobed leaves like tiny maple leaves.; vs Acaena: Poteridium fruits are smooth; Acaena fruits are covered in hooked spines.; vs Poterium: Poteridium leaflets are deeply lobed more than halfway; Poterium leaflets just have shallow teeth.; vs Sanguisorba: Poteridium leaflets are deeply dissected like fern fronds; Sanguisorba leaflets just have teeth along edges.
Frequently asked questions
Is Poteridium annuum native to California?
Yes. Poteridium annuum is native to California (recorded as native).
When does Poteridium annuum bloom?
Poteridium annuum blooms Apr-Jul.
Where in California does Poteridium annuum grow?
Poteridium annuum occurs in Modoc, Sierra, Nevada, Plumas, Butte, Tehama, Lassen, Siskiyou and other counties, at elevations of 225-1890 m.
What plant family does Poteridium annuum belong to?
Poteridium annuum is in the Rosaceae family, genus Poteridium.
What habitat does Poteridium annuum grow in?
Poteridium annuum grows in Open, especially disturbed areas.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · CalPhotos
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.