Plants 3-12+ dm. Stems puberulent, glabrescent. Leaves mostly cauline; blades ± lanceolate, 5-12(-20+) cm × 5-18(-40+) mm, l/w = 5-9(-14+), abaxially glabrate (pitted, with awl-shaped hairs in pits), adaxially scabrellous, resin-gland-dotted (sometimes pitted). Heads in congested, corymbiform arrays. Peduncles 1-8(-12+) mm. Involucres ± campanulate, 5-7(-8+) × 4-6 mm. Phyllaries 25-35+ in 4-5+ series, glabrescent, margins arachno-ciliolate, the outer lance-ovate, 1-3 mm, inner oblong to linear-oblong, 5-7+ mm, tips acute or rounded-apiculate. Florets 12-25+. Cypselae 3.5-4 mm; pappi fuscous to purplish, outer subulate scales or bristles 20-30, 0.5-3+ mm, intergrading with 35-45+, 5-7+ mm inner subulate scales or bristles. 2n = 34. Flowering Jul-Sep. Bottomlands, ditches, low prairies; 100-1200 m; Man.; Colo., Ill., Ind., Iowa, Kans., Ky., Mass., Minn., Mo., Nebr., N.Dak., Ohio, Okla., S.Dak., Wis.
From Flora of Indiana (1940) by Charles C. Deam
This species prefers a wet or prairie habitat and is found in sloughs in the Lower Wabash Bottoms, in wet marshes, and moist prairie habitats. It is infrequent and probably entirely absent from the southeastern part of the state although there are reports for it from that area.
Stems 3-14 dm, often red or purple, puberulent above, otherwise glabrous or nearly so; lvs denticulate to sharply serrate, glabrous, conspicuously pitted-punctate beneath; infl usually flat and dense, 4-10 cm wide; fls 10-26; invol 5-9 mm, its principal bracts rounded to subacute, entire or sparsely ciliate, commonly glabrous on the back; pappus tawny to purple; 2n=34. Wet prairies and marshes. The midwestern var. fasciculata, occurring from O., Ind., and Ky. to Minn., e. Nebr., e. Kans., and e. Okla., is 5-14 dm tall, with the middle cauline lvs 8-18 cm, narrowly to broadly lanceolate, glabrous above or minutely puberulent near the margin. The more western var. nebraskensis Gleason (V. corymbosa), occurring from s. Man. to Nebr. and ne. Colo., barely entering our range in w. Minn. and w. Io., is 3-6 dm tall, with the middle cauline lvs 4-10 cm, lance-ovate, scabrous above near the margins.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.