Perennials, 20-60+ cm (caudices relatively thick, fibrous-rooted). Stems erect, not branched (± scapiform). Leaves basal and cauline; alternate; ± petiolate (basal) or sessile; blades (usually appressed to strictly ascending) usually 1-nerved, linear to oblanceolate or spatulate, margins entire or remotely dentate (involute in C. pseudoliatris), faces glabrous or hairy, often gland-dotted. Heads discoid, in corymbiform to paniculiform arrays. Involucres campanulate to hemispheric, 3-12 mm diam. Phyllaries persistent, (5-)8-40 in (1-)2-5+ series, not notably nerved, ovate to elliptic or lanceolate, unequal (herbaceous to scarious). Receptacles convex, paleate or epaleate. Florets 12-35; corollas usually lavender to dark magenta or pinkish purple, sometimes blue, throats funnelform (sometimes externally gland-dotted, lengths 4-6 times diams.); styles: bases not enlarged, glabrous, branches linear-clavate (± papillose distally). Cypselae prismatic, ca. 10-ribbed, scabrellous to hispid-strigose, sometimes gland-dotted; pappi persistent, of 35-40, barbellulate to barbellate (subequal) bristles in 1-2 series. x = 10. Trilisa and Litrisa have been maintained as separate genera (R. M. King and H. Robinson 1987), distinguished primarily by their smaller heads with fewer phyllaries and their lack of receptacular paleae. In other features, their close similarity and relationship to Carphephorus seem evident, and other recent students of the group at species level (e.g., H. J.-C. Hebert 1968; M. D. Correa and R. L. Wilbur 1969; A. Cronquist 1980) have treated the species within a single genus. Forthcoming molecular studies suggest that one or both segregates may be justifiably recognized.
Heads discoid, the fls all tubular and perfect; invol bracts from few and subequal to numerous and imbricate; receptacle flat or nearly so, chaffy toward the margin in our spp.; cor pink-purple; style-branches papillate, elongate, linear or linear- clavate, with short ventromarginal stigmatic lines near the base; achenes 10-ribbed; pappus of 20-55 coarse, unequal, barbellate bristles in a single series; fibrous-rooted perennial herbs with alternate, entire, basally disposed lvs and several or many heads in a corymbiform to thyrsoid-paniculate infl. 7, se. U.S.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.