Plants 20-75 cm. Roots numerous, slender, mostly to 0.8 cm diam. Leaves persisting through anthesis, to 7, primarily basal reduced to sheathing bracts upward on stem, spreading, linear to linear-lanceolate, 10-25 × 1-5 cm. Spikes loosely to tightly spiraled, 4-7 flowers per cycle of spiral or nearly secund; rachis sparsely pubescent, some trichomes capitate, glands obviously stalked. Flowers white, rarely green; sepals distinct to base, 5.5-10 mm × 2-3 mm; lateral sepals clasping lip, appearing tubular; petals adhering to dorsal sepal, linear, 5-10 × 1-2 mm, apex subacute; lip oblong, 5.5-11 × 2-6 mm, apex dilated, margins often crenulate or toothed, glabrous on adaxial distal surface; veins raised, green, rarely cream colored, prominent, branches divergent, extending nearly to apex; basal calli straight, long-pointed, slender, mostly to 1 mm; viscidium linear-lanceolate; ovary mostly 5 mm. Seeds monoembryonic. Flowering Feb--Jun (Sep, north). Primarily on coastal plain and Gulf Coast in dry to moist roadsides, fields, pine flatwoods, pine savannas, cemeteries; 0--400 m; Ala., Ark., Del., Fla., Ga., La., Md., Miss., N.J., N.C., Okla., S.C., Tex., Va. Typical plants are easily recognized by the stark white flowers with green venation of the lip. In forma albolabia P. M. Brown & C. McCartney, the lip appears pure white but the raised veins are actually a pale yellow. Plants with creamy green to green flowers, usually in tight spirals, and incurved lateral sepals are local to frequent in north-central Florida and scattered westward in the Gulf counties to eastern Texas. Hybrids of Spiranthes praecox with S. vernalis are known as Spiranthes × meridionalis P. M. Brown.
Plants 2-8 dm; basal lvs narrow, to 20 cm, 3-10 mm wide; cauline sheaths 4-6, with blades to 10 cm; infl elongate, its axis minutely glandular-hairy, the fls closely spaced in a single spiral or the spiral sometimes so tight as to create 3 or 4 vertical files of fls, these spreading or slightly deflexed, urceolate-cylindric, 5-10 mm, mainly white, the oblong lip with a yellowish center and prominent divergent green veins, glabrous below and distally so above, its basal callosities 0.5-1.2 mm, higher than thick. Moist or wet open places on the coastal plain from N.J. to Fla. and Tex. June, July.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.