Plants erect, 10-35 cm. Leaves 3-4, along middle portion of stem, spiraled to alternate, ascending to spreading; blade narrowly elliptic to ovate-lanceolate or oblong, 5-11 × 1.3-3.5 cm. Flowers usually solitary (rarely 2 in forma biflorum P. M. Brown); sepals green with reddish brown markings; dorsal sepal broadly elliptic to ovate-lanceolate, 15-25 × 5-10 mm; lateral sepals distinct, 12-20 × 1.5-4 mm; petals somewhat spreading, same color as sepals, somewhat spirally twisted, linear- to linear-lanceolate, 11-24 × 1-2 mm; lip white with green apex, usually with extensive reddish reticulations often merging toward apex, adaxially swollen near middle, 10-16 mm, apex abruptly deflected downward, orifice basal, 7-12 mm; staminode suborbicular. 2n = 20. Flowering May--Jun. Dry to moist open coniferous and mixed forests, coniferous-forested fens, beach thickets; mostly 0--400 m; Man., N.S., Ont., Que., Sask.; Conn., Maine, Mass., Mich., Minn., N.H., N.Y., Vt., Wis.