Cirsium praeteriens

Biennials or perennials, probably more than 100 cm; rootstock unknown. Stems stout, erect, loosely arachnoid with fine trichomes and villous with jointed trichomes; branching unknown. Leaves: blades elliptic to oblanceolate, 15-30+ × 6-8+ cm, divided halfway or more to midveins, lobes linear-lanceolate, rigidly spreading, entire or trifid, acuminate, main spines stout, 5-15 mm, abaxial faces tomentose with fine, non-septate trichomes, villous along major veins with septate trichomes, adaxial glabrescent or sparsely tomentose, villous along veins; basal not observed; cauline well distributed, distally not much reduced, sessile, bases clasping, not decurrent. Heads 1-5, terminal and in distal axils in spiciform arrays. Peduncles 0-1 cm. Involucres hemispheric to broadly campanulate, 3-4 × 4-5+ cm, arachnoid. Phyllaries in 6-8 series, narrowly lanceolate to linear, outer subequal, rigidly spreading, spines 5-10 mm, inner ± imbricate, bodies appressed, glutinous ridge absent, apices spreading, margins spinulose or scabrid, apices of mid and inner flattened, spineless, scabrid. Corollas white, 30-33 mm, tubes 16 mm, throats 9-12 mm, lobes 5.5-9 mm; style tips 6 mm. Cypselae light brown, 6 mm, collars also light brown, ca. 0.75 mm; pappi 25-33 mm.

Flowering summer (Jun-Jul). Habitat unknown; of conservation concern; 0-100 m; Calif.

Cirsium praeteriens is known only from Santa Clara County, where J. W. Congdon collected it in Palo Alto in 1897 and 1901. It is presumed extinct.