Holocarpha heermannii
Heermann's tarweed
(c) Ken-ichi Ueda, some rights reserved (CC BY), uploaded by Ken-ichi Ueda · licence
Family: Asteraceae · Type: Herb · Native
Holocarpha heermannii (Heermann's tarweed) is a native California herb in the Asteraceae family, recognized by notably stalked-glandular stems and yellow-brown anthers are key.
Heermann's tarweed is a California native annual found in central Sierra Nevada Foothills, Tehama, San Joaquin Valley, eastern San Francisco Bay, southern Coast Ranges, and northern Western Transverse Ranges in grassland habitats at elevations below 1,400 meters. Flowering from May to November, this plant produces yellow flowers with yellow to brown anthers in heads with 3 to 13 ray flowers and 9 to 22 disk flowers. Growing with notably stalked-glandular stems that form panicle- or raceme-like clusters, it develops branches with distinctive flower heads. Its leaves are accompanied by heads with bell-shaped to nearly spherical involucres, each phyllary marked by 25 to 50 pit-gland-tipped outgrowths and minutely glandular surfaces. The plant's delicate, glandular structure and multiple flower heads make it a distinctive member of California's grassland ecosystems.
Identification and appearance
Key characters: 2 sympatric species; notably stalked-glandular stems and yellow-brown anthers are key
Habitat and range
Habitat: Grassland
Elevation: < 1400 m
Bloom period
Holocarpha heermannii blooms May-Nov.
How to tell it apart
vs Deinandra: Holocarpha has pit-gland-tipped stalk bracts; Deinandra stalk bracts lack pit glands.; vs Madia: Holocarpha has pit glands on stalk bracts; Madia lacks these distinctive pit glands.; vs Hemizonia: Holocarpha has pit-gland-tipped stalk bracts; Hemizonia stalk bracts lack pit glands.; vs Heterotheca: Holocarpha has yellow rays and pit-gland bracts; Heterotheca lacks pit glands, different flower structure.; vs Centromadia: Holocarpha has pit-gland-tipped stalk bracts; Centromadia lacks pit glands on bracts.
Frequently asked questions
Is Holocarpha heermannii native to California?
Yes. Holocarpha heermannii is native to California (recorded as native).
When does Holocarpha heermannii bloom?
Holocarpha heermannii blooms May-Nov.
What plant family does Holocarpha heermannii belong to?
Holocarpha heermannii is in the Asteraceae family, genus Holocarpha.
What habitat does Holocarpha heermannii grow in?
Holocarpha heermannii grows in Grassland.
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.