Eryngium armatum
Coastal button-celery
(c) Steve Matson, some rights reserved (CC BY), uploaded by Steve Matson · licence
Family: Apiaceae · Type: Herb · Native
Eryngium armatum (Coastal button-celery) is a native California herb in the Apiaceae family, recognized by leaf thickness and size highly diagnostic.
Coastal button-celery is a California native perennial found in coastal regions including northern Coast Ranges, San Francisco Bay Area, Suisun Marsh, and southern California coastal areas in coastal prairie, grassland, and marsh margins at elevations below 200 meters. Flowering from May to August, this plant produces white to pale purple flowers in small spherical heads 5 to 15 millimeters wide arranged in clustered cymes. Growing with decumbent to erect stems 10 to 50 centimeters tall, the plant features branching primarily 2 to 5 centimeters above its basal rosette. Its thick leaves are oblanceolate, reaching 10 to 30 centimeters long with sparse sharp serrations and occasional irregular pinnate cuts. The fruits are small, narrow-elliptic, measuring 1.5 to 2.5 millimeters and covered with dense, unequal pointed scales.
Identification and appearance
Key characters: 9 sympatric species; leaf thickness and size highly diagnostic
Habitat and range
Habitat: Coastal prairie, bluffs, grassland, marsh margins, often on clay soils
Elevation: < 200 m
California counties: Mendocino, San Luis Obispo, Santa Cruz, Monterey, Santa Barbara, Sonoma, Ventura, Marin, San Mateo, Contra Costa, Napa, San Benito, Humboldt, Alameda, Solano, San Diego
Bloom period
Eryngium armatum blooms May-Aug.
How to tell it apart
vs Navarretia: Eryngium has compact button-like heads; Navarretia has looser clusters with spine-tipped bracts radiating outward.; vs Dipsacus: Eryngium flower heads are round or cylindrical when young; teasel heads are elongated egg-shaped from the start.; vs Cirsium: Eryngium leaves are firm and waxy; thistle leaves are softer with white woolly undersides.; vs Plantago: Eryngium grows in wetlands with spiny bracts under each flower; plantain has ribbed leaves and lacks spiny bracts.; vs Sanicula: Eryngium has a single bract under each flower and a thistle-like appearance; Sanicula lacks individual bracts.
Frequently asked questions
Is Eryngium armatum native to California?
Yes. Eryngium armatum is native to California (recorded as native).
When does Eryngium armatum bloom?
Eryngium armatum blooms May-Aug.
Where in California does Eryngium armatum grow?
Eryngium armatum occurs in Mendocino, San Luis Obispo, Santa Cruz, Monterey, Santa Barbara, Sonoma, Ventura, Marin and other counties, at elevations of < 200 m.
What plant family does Eryngium armatum belong to?
Eryngium armatum is in the Apiaceae family, genus Eryngium.
What habitat does Eryngium armatum grow in?
Eryngium armatum grows in Coastal prairie, bluffs, grassland, marsh margins, often on clay soils.
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.