Appalachian twayblade, kidney-leaf twayblade

Listera reniformis Small, Bull. Torrey Bot. Club 24: 334. 1897, not D. Don 1825; Bifolium smallii (Wiegand) Nieuwland; Neottia smallii (Wiegand) Szlachetko; Ophrys smallii (Wiegand) House

Plants 5–35 cm. Stems slender, succulent, glabrous. Leaves: blade dark green, ovate-reniform, 2–4 × 1.5–3.5 cm, apex acute, mucronate, or apiculate to short-acuminate. Inflorescences 5–15-flowered, lax, 40–100 mm; floral bracts ovate, 3–4 × 1.5 mm, apex acute; peduncle and rachis glandular-pubescent. Flowers green, purple-brown, to pinkish tan; pedicel slender, 6–7 mm, glabrous; sepals strongly reflexed; dorsal sepal lanceolate to linear-lanceolate, 3–4 × 1 mm, apex acute; lateral sepals lanceolate to linear-lanceolate, 3–4 × 1 mm, apex acute; petals slightly reflexed, linear to linear-lanceolate, margins slightly revolute, apex acute; lip sessile, broadly obovate to cuneate, 6–10 × 5–7 mm, base with rounded lobule on each side, apex dilated and deeply cleft into pair of ± divergent broadly rounded lobes, shallowly toothed in sinus; column slightly arcuate, short, 1.5–3 × 1–2 mm. Capsules semierect, ellipsoid, 5 × 3 mm. 2n = 38.

Flowering Jun--Jul. Damp humus in shady forests of Appalachian Mountains, often beneath Rhododendron in acidic soil, also in sphagnous thickets and bogs; 600--1300 m; Ga., Ky., Md., N.J., N.C., Pa., S.C., Tenn., Va., W.Va.

Listera nipponica Makino, a species similar to L. smallii, occurs in the mountains of Japan.