Compact cobwebby thistle

Plants compactly branched, forming low rounded mounds, 5–100 cm, densely gray-tomentose. Leaf faces gray-tomentose or adaxial ± glabrate. Heads borne singly or in ± tight clusters, short-pedunculate, closely subtended and often overtopped by basal and large cauline leaves. Involucres wider than long, 5–8 cm diam., densely arachnoid with fine trichomes connecting tips of adjacent phyllaries. Phyllaries: imbricate to subequal, outer and mid apices ± spreading, straight, usually 1–2 cm × usually 1–2 mm. Corollas dark rose-purple, 25–30 mm. 2n = 30.

Flowering winter–summer (Feb–Jul). Coastal sea bluffs, dunes in grassland and coastal scrub; 0–50 m; of conservation concern; Calif.

Variety compactum is locally common along the immediate coast of northern San Luis Obispo County and formerly ranged as far north as San Francisco. Populations referable to this race occur on the California Channel Islands and on the mainland in Monterey County. Because of the very narrow ecologic zone occupied by these plants they are particularly vulnerable to habitat loss. Variety compactum is closely related to vars. occidentale and coulteri.