Perennials, 30-70 cm. Internodes (± mid stem) (1-)8-12+ cm. Leaves basal and cauline; usually alternate, sometimes opposite and alternate or all opposite; petioles 1-10(-15+) cm, not ciliate; blades elliptic or lanceolate to ± linear, (2-)4-8(-15+) cm × (3-)7-12(-40+) mm, sometimes with 1-2 lateral lobes. Peduncles (1-)4-8(-10+) cm. Calyculi of broadly deltate-ovate to lance-ovate or lance-linear bractlets 2-6+ mm. Phyllaries lance-ovate to lanceolate, 6-9(-12) mm. Ray laminae yellow, (12-)15-20+ mm. Disc florets 40-80+; corollas purplish or purple-tipped, 2.8-4.8 mm. Cypselae ± obovate to oblong, 3-4 mm, winged, wings 0.2-0.4+ mm wide, ± pectinate; pappi of 2 subulate scales 0.5-1+ mm. 2n = 26. Flowering ± year round, mostly Sep-Oct. Peaty bogs, swamps, depressions, in pine barrens; 10-100+ m; Ala., Ark., Fla., Ga., La., Miss., N.C., S.C., Tex., Va. As here circumscribed, Coreopsis gladiata includes plants that others (without agreement among themselves) have treated as distinct species and/or varieties: C. falcata (leaves mostly basal and/or proximal, alternate, blades mostly lance-linear to linear, often 1-2 with 1-2 lateral lobes, faces not dotted; outer phyllaries lance-ovate to lance-linear; Ga., N.C., S.C.); C. floridana (leaves mostly basal and/or proximal, alternate, blades mostly lance-linear to linear, not lobed, not dotted; outer phyllaries broadly deltate-ovate; Fla.), C. helianthoides (leaves mostly cauline, alternate, blades mostly elliptic to lanceolate, not lobed, faces not dotted; outer phyllaries lance-ovate to lance-linear; Ala., Fla., Ga., La., Miss., N.C., S.C.), and C. linifolia (leaves basal and cauline or mostly cauline, alternate or opposite or both, blades mostly lance-linear to linear, seldom lobed, faces bearing dark or translucent dots; outer phyllaries lance-ovate to lance-linear; Ala., Fla., Ga., La., Miss., N.C., S.C., Tex., Va.).
Short-lived, fibrous-rooted, glabrous perennial 5-12 dm; lvs mostly entire, the lower oblanceolate or spatulate, conspicuously long-petiolate, to 30 נ3.5 cm, or much smaller, middle cauline lvs reduced, linear, the upper mere upper bracts; heads several, the disk 6-18 mm wide, dark purplish; outer invol bracts much shorter than the inner; rays yellow, 1-2.5 cm; receptacular bracts linear, acute; disk-fls 4-toothed; style-appendages short and blunt; achenes oblong, 2-4.5 mm, the wings deeply and subpectinately lacerate; pappus of 2 short, upward barbed awns; 2n=26, 52, 156. Wet, often acid places; coastal plain from s. Va. to Fla. and Tex. Sept., Oct. Ours is var. linifolia (Nutt.) Cronquist, with the lvs minutely dark-dotted in transmitted light in life, many of or all the lvs opposite, the lower to ca 1 cm wide, not greatly elongate. (C. angustifolia; C. oniscicarpa) The var. gladiata, with the lvs not dark-dotted, all or nearly all alternate, the lower much elongate and mostly 1-3.5 cm wide, probably does not reach our range. (C. falcata; C. longifolia)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.