Plants 9-25 cm. Pseudobulbs ovoid, 20 ×10 mm, sheathed by bracts and persistent leaf bases, previous year´s pseudobulb usually present, connected by short rhizome. Stems bright green, with or without purplish brown tinge, angled, sometimes obscurely winged or fluted distally. Leaves 2; blade conduplicate, dark green, glossy, ovate-elliptic, keeled abaxially, 4-18 × 2-8.5 cm, succulent, apex obtuse to acute. Inflorescences 4-15 cm; floral bracts subulate, 2 × 1 mm, apex acute; pedicels slender, 5-7 mm. Flowers 5-31, mauve-purple and green; dorsal sepal oblong-lanceolate to narrowly lanceolate, 8-11.5 × 1.2-2 mm, apex obtuse to acute; lateral sepals oblong-lanceolate to narrowly lanceolate, 8-11.5 × 1.2-2 mm, apex obtuse to acute; petals pendent, curved, tubular, narrowly linear to filiform, 8.5-12 × 0.2-0.3 mm, margins strongly revolute; lip translucent, mauve to pale purple or rarely green with prominent purplish veining, cuneate-obovate to suborbiculate, 8-12 × 6-10 mm, base slightly auriculate, apical margin erose-serrulate, apex subtruncate, mucro-nate; column winged apically, 3-4 × 1-1.5 mm, with 2 blunt tubercles on inner surface near base; anthers yellow; pollinia yellow. Capsules: pedicel 11-18 mm; body ellipsoid, 15 × 5 mm, veins often slightly winged. Flowering May--Jul (north). Mature mesic to moist deciduous forests, pine woods, rich moist humus, often colonizing previously open, disturbed habitats during early and middle stages of reforestation; 10--1500 m; Ont.; Ala., Ark., Conn., Del., Ga., Ill., Ind., Iowa, Ky., Md., Mass., Minn., Miss., Mo., N.H., N.J., N.Y., N.C., Ohio, Okla., Pa., R.I., S.C., Tenn., Vt., Va., W.Va., Wis. Liparis liliifolia has what appear to be extremely similar relatives in Japan [L. japonica (Miquel) Maximowicz and L. makinoana Schlechter] and China (L. pauliana Handel-Mazzetti and L. cathcartii Hooker f.). Further work is needed to clarify the relationships among these five species. It could be a case of either divergent evolution from a common ancestor or convergent evolution from two or more ancestors.