Gen. Sp. Orchid. Pl., 467. 1840.
Plants 15–50 cm. Roots numerous, mostly to 1 cm diam., stout. Leaves fugacious or persisting through anthesis, to 3–5, cauline, reduced to sheathing bracts upward on stem, spreading, linear-lanceolate, keeled, 5–15 × 0.5 cm, rigid. Inflorescences: spikes loosely to tightly spiraled, usually no more than 180°, 5–9 flowers per cycle of spiral, sometimes secund; rachis sparsely pubescent, some trichomes capitate, glands obviously stalked. Flowers mostly horizontal, strongly gaping, white to cream; sepals distinct to base, lanceolate, tapering in distal 1/3, (8–)9–10 × 2–3 mm; lateral sepals widely spreading; petals linear, slightly falcate, 7–9 × 2–2.5 mm; lip yellow centrally, ovate in general outline, base rounded-dilated, apical portion descending, oblong, 8–11 × 4 mm, apex recurved with margin crisped; basal calli erect, tapered, to 1 mm; viscidium linear-lanceolate; ovary mostly 7 mm. Seeds monoembryonic.
Phenology: Flowering Oct–Dec.
Habitat: Primarily on coastal plain in dry to moist meadows, pine flatwoods and savannas, fields, roadsides
Elevation: 0–50 m
Ala., Fla., Ga., La., Miss., N.C., S.C., Tex., Va.
Hybrids of Spiranthes longilabris and S. odorata are known as Spiranthes ×folsomii P. M. Brown.