Cirsium hydrophilum var. vaseyi

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.