Hemizonia congesta subsp. calyculata
Mendocino tarplant, Mendocino Tarplant
Photo: parent species Hemizonia congesta · (c) Bruce Homer-Smith, some rights reserved (CC BY) · licence
Family: Asteraceae · Type: Herb · Native
Conservation status: CNPS 4.3
Hemizonia congesta subsp. calyculata (Mendocino tarplant) is a native California herb in the Asteraceae family, recognized by 5 sympatric subspecies. Key diagnostic: calyx-like bracts 5-7, bracts > phyllaries.
Mendocino tarplant is a California native annual herb found in the northern California Coast Ranges in grassland and woodland openings at elevations of 200 to 1,400 meters. Flowering from July to November, this plant produces white ray flowers with purple veins and yellow disk flowers in compact clusters. Growing with glandular, bristly stems up to 50 centimeters tall, it develops densely clustered side branches with nearly sessile flower heads. Its leaves are minutely bristly, coarse-hairy, and densely covered with stalked glands, with distal leaves being particularly glandular. The fruit is small, with a width approximately half its length.
Identification and appearance
Key characters: 5 sympatric subspecies. Key diagnostic: calyx-like bracts 5-7, bracts > phyllaries
Habitat and range
Habitat: Clay soils, grassland, openings in woodland
Elevation: 200-1400 m
Bloom period
Hemizonia congesta subsp. calyculata blooms Jul-Nov.
Conservation status
CNPS 4.3
How to tell it apart
vs Deinandra: Hemizonia rays often purple-veined beneath; Deinandra rays pure yellow without veining.; vs Madia: Hemizonia has paleae throughout disk; Madia has ray fruits enclosed by phyllaries.; vs Calycadenia: Hemizonia rays shallowly lobed; Calycadenia rays deeply split into spreading lobes.; vs Holocarpha: Hemizonia lacks pit glands on stalks; Holocarpha has distinctive pit-gland-tipped stalk bracts.; vs Anisocarpus: Hemizonia has chaff throughout flower disk; Anisocarpus typically lacks chaff scales.
Frequently asked questions
Is Hemizonia congesta subsp. calyculata native to California?
Yes. Hemizonia congesta subsp. calyculata is native to California (recorded as native).
When does Hemizonia congesta subsp. calyculata bloom?
Hemizonia congesta subsp. calyculata blooms Jul-Nov.
What plant family does Hemizonia congesta subsp. calyculata belong to?
Hemizonia congesta subsp. calyculata is in the Asteraceae family, genus Hemizonia.
Is Hemizonia congesta subsp. calyculata rare or endangered?
Hemizonia congesta subsp. calyculata carries California Rare Plant Rank 4.3, state rank S4.
What habitat does Hemizonia congesta subsp. calyculata grow in?
Hemizonia congesta subsp. calyculata grows in Clay soils, grassland, openings in woodland.
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.