Cirsium scariosum var. americanum
Dinnerplate thistle
(c) Matt Lavin, some rights reserved (CC BY-SA) · licence
Family: Asteraceae · Type: Perennial · Native
Cirsium scariosum var. americanum (Dinnerplate thistle) is a native California perennial in the Asteraceae family, recognized by stemless habit and high elevation meadow habitat diagnostic.
Dinnerplate thistle is a California native perennial found in the high Sierra Nevada, Warner Mountains, and high Cascade Range in wet to dry meadows, grassy forest openings, and open sites at elevations of 1,600 to 3,500 meters. Flowering from June to August, this plant produces white to pink-tinged flowers in heads 1.5 to 3 centimeters wide, clustered closely around a basal rosette. Growing without a prominent stem, it forms dense clusters with leaves that are glabrous on the upper surface and covered in gray woolly hairs underneath. Its leaves feature distinctive spines 2 to 7 millimeters long, with outer phyllary spines ranging from 1 to 12 millimeters. The involucre has inner phyllary tips that are either entire or expanded into irregular scarious appendages.
Identification and appearance
Key characters: 20 sympatric species; stemless habit and high elevation meadow habitat diagnostic
Habitat and range
Habitat: Wet to dry meadows, grassy forest openings, open sites
Elevation: 1600-3500 m
California counties: Nevada, Shasta, El Dorado, Sierra, Lassen, Mono, Plumas, Modoc, Mariposa, Tulare, Placer, Tuolumne, Butte, Fresno, Alpine, Inyo, San Diego
Outside California: to Oregon, Idaho, Wyoming, Colorado, northern Baja California
Bloom period
Cirsium scariosum var. americanum blooms Jun-Aug.
How to tell it apart
vs Carduus: Cirsium has fluffy, feathery seed tufts; Carduus has rough bristles or no pappus and continuous spiny wings down the stem.; vs Silybum: Cirsium leaves are plain green; Silybum has bright white marbling along the leaf veins.; vs Sonchus: Cirsium has thistle-type flowers with spine-tipped bracts; Sonchus has dandelion-like flowers and milky sap.; vs Cynara: Cirsium heads are 1-6 cm across; Cynara heads are massive (4-15 cm, tennis ball sized) with fleshy bases.; vs Centaurea: Cirsium has linear bracts without appendages; Centaurea bracts have fringed or comb-like tips.
Frequently asked questions
Is Cirsium scariosum var. americanum native to California?
Yes. Cirsium scariosum var. americanum is native to California (recorded as native).
When does Cirsium scariosum var. americanum bloom?
Cirsium scariosum var. americanum blooms Jun-Aug.
Where in California does Cirsium scariosum var. americanum grow?
Cirsium scariosum var. americanum occurs in Nevada, Shasta, El Dorado, Sierra, Lassen, Mono, Plumas, Modoc and other counties, at elevations of 1600-3500 m.
What plant family does Cirsium scariosum var. americanum belong to?
Cirsium scariosum var. americanum is in the Asteraceae family, genus Cirsium.
What habitat does Cirsium scariosum var. americanum grow in?
Cirsium scariosum var. americanum grows in Wet to dry meadows, grassy forest openings, open sites.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · CalPhotos
Last updated 2026-09-30
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.