Cirsium ownbeyi

Perennials, 30-70 cm; taproots and branched caudices with persistent dark-brown leaf bases. Stems 1-several, erect, simple or sparingly branched in distal ¹/2, glabrous or thinly arachnoid and sparingly villous with jointed trichomes. Leaves: blades oblong to elliptic or oblanceolate, 15-30+ × 2-7 cm, deeply 2-3-pinnately divided, lobes linear to linear-lanceolate, spinulose to spiny-dentate or shallowly lobed, main spines slender, 2-8 mm, abaxial faces glabrous to thinly tomentose and villous along major veins, soon glabrescent, adaxial glabrous; basal present at flowering, narrowly spiny winged-petiolate; principal cauline well distributed, proximal winged-petiolate, mid and distal sessile, gradually reduced, bases decurrent as spiny wings 1-3 cm; distalmost reduced to spiny-pectinate bracts. Heads 1-few, erect, ± crowded in corymbiform arrays. Peduncles 0-4 cm. Involucres ovoid, 1.8-2.5 cm, 1.5-2.5 cm diam., loosely arachnoid, glabrate. Phyllaries in 5-6 series, imbricate, green, linear-lanceolate, abaxial faces without or with poorly developed glutinous ridge; outer and mid bases appressed, apices stiffly radiating to ascending, long, very narrow, entire, spines slender, 3-10 mm; apices of inner straight, flexuous. Corollas white to pink or pink-purple, 16-20 mm, tubes 6-8 mm, throats 5-6 mm, lobes 5-7 mm; style tips 3.5-4.5 mm. Cypselae brown, ca. 4 mm, apical collars not differentiated; pappi 13-17 mm.

Flowering summer (Jun-Aug). Stony soils in sparsely vegetated areas of pinyon-juniper woodlands, sagebrush scrub, arid grasslands, and riparian scrub, in dry sites or sometimes on seeps; 1500-2400 m; Colo., Utah, Wyo.

Cirsium ownbeyi is endemic to the eastern side of the Uintah Mountains in northeastern Utah, southwestern Wyoming, and northwestern Colorado. It is in the Center for Plant Conservation´s National Collection of Endangered Plants.