Protologue Description: BIDENS EATONI. Annual, simple or freely branched, 2.5 to 6 dm. high: leaves simple, lanceolate, with long-acuminate tips and slender petiolar bases, coarsely and often deeply serrate, 5-15 cm. long: heads erect, cylindric or oblong, in fruit becoming obovoid, longer than broad: outer involucre usually of 3 to 5 foliaceous bracts slightly exceeding the disk: inner involucre mostly of 5 oblong blunt or barely mucronate conspicuously striate bracts about 1 cm. long, equalling the disk: rays none: disk flowers 15-25: achenes flatish; the inner 7 to 9 mm. long, 1 to 1.7 mm. broad, with well developed but narrow midribs, linear-oblanceolate, usually with retorse hairs on the margins; awns 2 to 4, downwardly barbe, the marginal longest, 3 to 4.3 mm. long, about equalling the pale yellow corollas- Brackish shores of the Merrimac River, Newburyport, Massachusetts, Sept. 1902 (A.A. Eaton), Newburyport and Salisbury, Oct. 2, 1902 (A.A. Eaton & M.L. Fernald).