Perennials, 15-60 cm; rhizomatous, fibrous-rooted, primary rhizomes relatively slender, producing slender, herbaceous, scale-leaved, stoloniform rhizomes (rhizomes often not collected). Stems erect to ascending (usually abruptly dilated proximal to heads), villous (more densely so on proximal 1 / 2 ), eglandular. Leaves basal (persistent) and cauline; basal blades oblanceolate to obovate or suborbiculate, subspatulate, 20-130(-180) × 6-30(-50) mm, cauline gradually reduced distally (bases clasping and slightly auriculate), margins usually dentate to denticulate, rarely entire, faces sparsely to moderately hirsute to hirsuto-villous, sometimes glabrate or glabrous (especially adaxially), eglandular. Heads 1-4(-9). Involucres 5-7 × 6-20 mm. Phyllaries in 2-3(-4) series, sparsely to moderately hirsute to hirsuto-villous (cross walls not distinctly colored), minutely glandular to stipitate-glandular. Ray florets 50-80(-100); corollas light blue to purplish, pink, or white, 6-10 mm, laminae coiling tardily at tips. Disc corollas 4.5-6 mm. Cypselae 1.3-1.8 mm, 2(-4)-nerved, faces sparsely strigose to glabrate or glabrous; pappi: outer 0 or of setae, inner of (22-)28-36 bristles.
Plants 1.5-6 dm from a short, fibrous-rooted caudex, perennating by slender, stoloniform rhizomes; basal lvs oblanceolate to suborbicular, 2-13 cm נ6-50 mm, commonly toothed; cauline lvs ovate to lanceolate or oblong, reduced upwards; heads solitary or few; invol 5-7 mm; disk 10-20 mm wide; rays 50-100, 6-10 mm, ca 1 mm wide or a little more, blue, or sometimes pink or white; disk-cors 4.0-6.0 mm; pappus simple; 2n=18. Woods and
streambanks; Me. to Ont. and e.c. Minn., s. to Ga., Miss. and e. Tex. Three vars.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.