Mount Tamalpais or Vasey’s thistle

Cnicus breweri A. Gray var. vaseyi A. Gray in A. Gray et al., Syn. Fl. N. Amer. 1(2): 404. 1884; Cirsium montigenum Petrak; C. vaseyi (A. Gray) Jepson

Heads usually 3–3.5 cm. Cypselae oblong or elliptic, 4–5 mm. 2n = 32.

Flowering spring–summer (May–Jul). Spring-fed marshy meadows on serpentine parent material in areas of chaparral and mixed evergreen forest; of conservation concern; 300–500 m; Calif.

Variety vaseyi is endemic to the slopes of Mt. Tamalpais in the southern North Coast Range of Marin County, California.