Herbs, clonal, rhizomatous, 4-40 cm. Stems purplish to brownish green, glaucous; scales 2-4, typically below soil line, purplish. Leaves green adaxially; blade oblong-lanceolate, obovate, or elliptic, 25-100 × 10-53 mm, apex obtuse to acuminate, sometimes glaucous abaxially. Flowers pedunculate, showy, sweetly fragrant, without nectar; sepals spreading, purplish brown, narrowly lanceolate, 34-67 × 2-4 mm; petals yellowish green, elliptic-obovate to elliptic-lanceolate, 15-25 × 3-7 mm; lip yellowish green to white, streaked with purple, oblong, 15-25 × 8-9 mm, lateral lobes streaked with purple, margins involute, middle lobe rounded, margins revolute, undulate; callus green, longitudinal, fleshy; column 8-12 mm; ovary 20-30 mm; rostellar flap prominent. Capsules 20-42 × 5-10 mm; pedicel of mature capsule elongating to 20-55 mm. 2n = 18. Flowering Apr--Jun. Acidic soils, in dry to mesic forests, seeps, sphagnum bogs; 10--2000 m; Ont.; Ala., Ark., Conn., Del., Fla., Ga., Ill., Ind., Ky., La., Maine, Md., Mass., Mich., Miss., Mo., N.H., N.J., N.Y., N.C., Ohio, Okla., Pa., R.I., S.C., Tenn., Tex., Vt., Va., W.Va. Isotria verticillata frequently forms extensive clones with hundreds of stems. It is pollinated by solitary bees of the Andrenidae, Anthophoridae, and Halictidae; plants are apparently self-compatible (L. A. Mehrhoff 1983). Nonflowering plants only rarely have a white, arrested floral bud (1-2 mm).