Plants 2-8 dm, simple or often freely branched; lvs sessile, lanceolate or lance-ovate, acute or subacuminate, 2-7 cm; fls blue or seldom white, in dense cymes terminating the stem or short axillary branches, on pedicels to 1 cm, or a few lower fls solitary; cal-lobes linear to lance-ovate; cor 15-23 mm, tubular-funnelform, blue to white, its lobes 4-7 mm, ovate or lance-ovate, acute or acuminate; 2n=38. Woods and moist or wet open places. Aug., Sept. Var. quinquefolia, with the cal-tube 1.5-3 mm, and the cal-lobes 1.5-5 mm, occurs in the Appalachian region from Me. to Ga., w. to w. N.Y. and adj. Ont. (Gentiana q.) Var. occidentalis (A. Gray) Small, with the cal-tube 2.5-5 mm and the lobes 4.5-10 mm (often foliaceous), is more western, occurring from O. and s. Ont. to Minn., s. to Ky., Ark., and se. Kansas. (G. o.; Amarella o.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.