Perennials, 30-60 cm. Stems erect, glabrous. Leaves opposite; petioles 25-70 mm; blades broadly ovate-deltate, 4-8 × 5-9 cm, (thin, delicate) bases truncate to subcordate, margins coarsely dentate, apices acute to acuminate, abaxial faces glabrous or sparsely puberulent. Heads clustered. Peduncles 1-3 mm, glabrous or sparsely puberulent. Involucres 3.5-4 mm. Phyllaries: apices acuminate, abaxial faces glabrous or sparsely puberulent. Corollas white, lobes glabrous or sparsely puberulent. Cypselae sparsely and evenly hirtellous. 2n = 34.

Flowering Aug-Oct. Under overhanging sandstone (Pottsville formation) cliffs and ledges; 400-500 m; Ky., Tenn.

Resembling no. 9 [Eupatorium rugosum Houttuyn.], but more delicate and slender, 3-6 dm, often glabrous throughout; lvs very thin, deltoid or subcordate, about as broad as long, coarsely and irregularly dentate, the petiole nearly or fully as long as the blade; invol bracts attenuate- acuminate. Under overhanging sandstone cliffs; Cumberland Plateau region of s. Ky. and n. Tenn. Sept.

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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