Rhizomatous perennial 1-8 dm, ±villous throughout; lvs scarcely punctate, the cauline 5-20 נ1.5-8 cm, the basal often longer and persistent, all bi- or tripinnatifid, with narrow ultimate segments, the main rachis scarcely or not at all winged, that of each pinna only narrowly so; heads 1-15, rarely more, the disk 10-18 mm wide; rays inconspicuous or more commonly evident, to 4 mm; 2n=54. Beaches and riverbanks; Me. and Nf. to n. Mich., n. Wis., and Alas. July-Aug. Closely allied to the Siberian and Alaskan T. bipinnatum (L.) Sch. Bip.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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