Perennials or subshrubs, 30-100 cm. Stems (erect, striate-angled) glabrous, not glaucous. Leaves ascending to spreading-ascending; blades 3- or -5-nerved, lanceolate to narrowly lanceolate, 40-80 × 3-6(-9) mm, lengths 8-18 times widths, abruptly reduced distally, firm-herbaceous, margins scabrous, apices mostly acute, faces glabrous, little and obscurely gland-dotted (9-29 dots per mm²), sometimes pustulate. Heads glomerate or pedunculate, in compact, usually round-topped arrays 6-35% of plant heights. Involucres obconic, 4-6 mm. Phyllaries yellowish at bases, usually green-tipped, outer narrowly ovate, inner nearly linear, apices rounded to subacute (sometimes slightly resinous). Ray florets usually 7-14. Disc florets 3-6; corollas 3.3-4.4 mm. 2n = 18. Flowering Sep-Nov. Moist, sandy soils of open areas, woodlands, and forest openings; 0-100 m; Ala., Ark., Fla., Ga., La., Miss., Mo., N.C., Okla., Tenn., Tex. I have seen no specimens of Euthamia leptocephala from Kentucky; it is to be expected there.
Similar to no. 5 [Euthamia gymnospermoides Greene], but much less resinous, the lvs only sparsely or obscurely punctate, or sometimes more closely and evidently so, but the punctae then with scanty resin and appearing somewhat pustulate; lvs 4-8 cm נ3-6 mm, 10-20 times as long as wide; invol only slightly or scarcely glutinous; lvs 3-7 mm wide; 2n=18, 54. Open, often moist and sandy places and thin woods; s. Mo. to s. Ill. and c. Tenn., s. to Tex., La., Miss., and w. Fla. (Solidago l.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.