Plants (20-)40-110(-180) cm. Corms globose to slightly elongate. Stems glabrous. Leaves: basal and lower cauline 3-5-nerved, narrowly oblong-lanceolate to narrowly spatulate-oblanceolate, 120-350 × (2-)4-10(-20) mm (sometimes becoming more densely arranged distally), usually gradually reduced distally, essentially glabrous or sparsely villous, weakly gland-dotted (glandular hairs often not evident, bases of basal often fibrous-persistent). Heads in dense to loose, spiciform arrays. Peduncles usually 0, rarely 1-2 mm. Involucres turbinate-cylindric to turbinate-campanulate, 7-11 × 4-6 mm. Phyllaries in (3-)4-5 series, ovate to oblong, unequal, essentially glabrous, margins with hyaline borders, sometimes ciliolate, apices rounded to obtuse. Florets (4-)5-8(-14); corolla tubes glabrous inside. Cypselae (3.5-)4.5-6 mm; pappi: lengths ± equaling corollas, bristles barbellate. Liatris spicata is sold as cut flowers. It also is commonly sold as a garden plant in various genetic permutations (probably derived from var. spicata, perhaps from L. lancifolia) and it apparently escapes cultivation. Reports from Arkansas, Connecticut, and Quebec probably reflect plants growing in or escaped from gardens.
A geographic disjunction within Liatris spicata occurs between the coastal plain element (var. resinosa) and the inland/montane element (var. spicata), although plants morphologically referable to var. resinosa occasionally are encountered in montane North Carolina and Tennessee and var. spicata-like plants occur in the range of var. resinosa. Apparent intergrades between the two taxa are common, especially in Tennessee and Alabama. The geographical gap is widest in Georgia and Alabama. Neither variety occurs naturally west of the Mississippi River, except for a historical record of var. spicata in Oregon County, Missouri (Kellogg s.n., MO), where the population has now been genetically 'swamped' by L. pycnostachya (G. A. Yatskievych, pers. comm.).
In both var. spicata and var. resinosa, marked variation (dimorphism) in head size occurs, the large-headed plants apparently occurring in scattered geographic enclaves without a broader geographic pattern. It seems possible that independent populational origins of polyploidy might underlie the variation.
Glabrous or seldom somewhat hirsute, 6-20 dm; lvs numerous, linear or nearly so, the lowest ones 10-40 cm נ(2-)5-20 mm, the others reduced upward; heads sessile, crowded into an elongate, densely spiciform infl; axis of the infl glabrous; invol subcylindric or narrowly turbinate-campanulate, 7-11 mm, its bracts narrowly scarious-margined, often anthocyanic, at least the inner ones mostly rounded or broadly obtuse, the outer sometimes acutish; fls (5)6-10(-14) per head, the cor glabrous within, 7-11 mm including the 2-3 mm lobes; pappus barbellate; 2n=20. Wet meadows and other moist, open places; N.Y. to Mich. and se. Wis., s. to Fla. and La., and occasionally w. to Wyo. and N.M. July-Sept.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.