Biennials or monocarpic perennials, 100-300 cm; taproots short with many slender, fibrous lateral roots. Stems usually 1, erect, glabrous to ± tomentose; branches many, usually restricted to distal part of stem, ascending. Leaves: blades oblong to elliptic, 10-60 × 5-20 cm, unlobed and merely spinulose to irregularly dentate or shallowly to deeply pinnatifid, lobes ± broadly triangular, separated by wide sinuses, obtuse to acute, sometimes coarsely toothed or lobed, main spines slender, 1-3 mm, faces thinly arachnoid, soon glabrescent; basal often present at flowering, petioles slender, ± winged; cauline progressively reduced, proximal petiolate, mid and distal sessile, long-decurrent; distalmost linear to narrowly elliptic, bractlike, spinulose to irregularly dentate or shallowly lobed. Heads many, in openly paniculiform arrays, borne singly at tips of peduncles. Peduncles slender, 1-15 cm. Involucres ovoid to hemispheric, 1-2 × 1-2 cm, thinly arachnoid, glabrate. Phyllaries in 8-9 series, strongly imbricate, green, lanceolate (outer) to linear (inner), abaxial faces with prominent glutinous ridge; outer and middle appressed, bodies entire, apices acute, spines spreading, slender, ca. 1 mm; apices of inner often flexuous, acuminate, flat, scabrid-ciliolate. Corollas white to pink-purple, 19-21 mm, tubes 9-10 mm, throats 4-4.5 mm, lobes 5-7 mm; style tips 2-3.5 mm. Cypselae brown, ca. 4.5 mm, apical collars stramineous, 0.2 mm; pappi 15-16 mm. Flowering summer-fall (Aug-Oct). Springs, seeps, marshes, stream banks, often in alkaline soil; of conservation concern; 1100-2600 m; Ariz., N.Mex., Tex.; Mexico (Chihuahua, Sonora). Wright´s thistle occurs from the mountains of south-central New Mexico eastward to the cienegas of the adjacent southwestern Great Plains. Cirsium wrightii is listed by the state of New Mexico as a species of concern. The one known site in Cochise County, Arizona, is apparently historic.

Hybrids are known between Cirsium wrightii and C. vinaceum in the Sacramento Mountains of New Mexico. I have observed hummingbird visits to the heads of both species, though C. wrightii shows none of the apparent adaptations to hummingbirds (P. L. Barlow-Irick 2002) that are seen in such taxa as C. occidentale var. candidissimum, C. andersonii, and C. arizonicum.