Cirsium remotifolium var. rivulare
Klamath thistle
Photo: parent species Cirsium remotifolium · (c) Trevor Van Loon, some rights reserved (CC BY), uploaded by Trevor Van Loon · licence
Family: Asteraceae · Type: Perennial · Native
Cirsium remotifolium var. rivulare (Klamath thistle) is a native California perennial in the Asteraceae family, recognized by purple flowers and ciliate phyllaries.
Klamath thistle is a California native perennial found in northern northwestern California in grassy areas, woodland openings, and forest habitats at elevations below 750 meters. Flowering from May to August, this plant produces purple flowers in thistle heads with delicate linear phyllaries edged with tiny spreading spines. Growing with upright stems to moderate height, it develops robust branching characteristic of thistles. Its leaves feature intricate serrated edges typical of the Cirsium genus, with potential variation between lower and upper stem foliage. The flower's purple corolla spans 19 to 25 millimeters long, with a distinctive tube and lobed structure creating an elegant botanical profile.
Identification and appearance
Key characters: 22 sympatric species; purple flowers and ciliate phyllaries help distinguish
Habitat and range
Habitat: Grassy areas, openings in woodland, forest
Elevation: < 750 m
Outside California: Oregon
Bloom period
Cirsium remotifolium var. rivulare blooms May-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 remotifolium var. rivulare native to California?
Yes. Cirsium remotifolium var. rivulare is native to California (recorded as native).
When does Cirsium remotifolium var. rivulare bloom?
Cirsium remotifolium var. rivulare blooms May-Aug.
What plant family does Cirsium remotifolium var. rivulare belong to?
Cirsium remotifolium var. rivulare is in the Asteraceae family, genus Cirsium.
What habitat does Cirsium remotifolium var. rivulare grow in?
Cirsium remotifolium var. rivulare grows in Grassy areas, openings in woodland, forest.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · 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.