A terrestrial herb with a short stout rhizome and fibrous roots, often forming large clumps. Erect stems typically slender, sparsely pubescent, 15-35 cm tall, leafy above covered by three sheaths below. Leaves three or four (rarely five), strongly two-ranked, suberect, commonly conduplicate, sheathing at base, lanceolate or ovate-lanceolate, acute or acuminate, 5-15 cm long, 2-8 cm wide, bluish green, pubescent on veins above and below, ciliate. Inflorescence one- or two-flowered; rhachis slender, glandular hairy; bracts leaf-like, lanceolate, acuminate, 3-8 cm long, 1-3 cm wide, pubescent and ciliate... Flowers small, showy, fragrant, the sepals and petals madder purple to maroon, glossy, the lip yellow with red spotting inside, the staminade yellow with red spotting; pedicel and ovary subsessile 1.5 cm long. Dorsal sepal suberect, lanceolateovate, acuminate, 2-4 cm long, 1.5-2.5 cm wide, undulate. Synsepal similar, slightly incurved, bifid at the apex, 2-4 cm long. Petals spirally twisted two to four times, linear-tapering, acute, 3-5 cm long, 0.5-0.8 cm wide, pubescent within in basal half. Lip porrect, obovoid to ellipsoidal, with a small mouth, 1.5-2.8 cm long, 1.2-2 cm wide, the apical margins incurved, the incurved sides with a basal pleat. Column short, 0.6 cm long; staminode subsessile, trullate, blunt, concave in apical half, 0.8-1 cm long, 0.5-0.6 cm wide; filaments extend beyond anthers, blunt to acute.
In sunny places in damp calcareous fens, non-sphagnous bogs, marshes and meadows with Mertensia and skunk cabbage, in wet prairies where sedge, shrubby cinquefoil, poison sumac and red osier dogwood abound, in marly cedar swamps and in deciduous woodland, favouring drier, often more acidic sites than var. pubescens.