Plants 6-40 cm. Pseudobulbs 5-15 mm diam. Leaves 1(-2, rarely), near middle of stem; blade green, glossy, oval or broadly elliptic, cordate, 3-9 × (1.2-)3-6.4 cm, apex acute. Inflorescences corymbose racemes, 1.5-3 cm; floral bracts triangular, 0.8-1.2(-2.5) mm, apex acute; pedicels crowded. Flowers 10-33, resupinate, green; sepals recurved at apex, ovate-elliptic or lanceolate, (2.8-) 3.6-4.2 × 1.4-1(-2) mm, apex subobtuse to acute; petals strongly reflexed, crossing behind flower, linear to filiform, (2-)3.5-4 × 0.2-0.6 mm, apex obtuse; lip triangular, 3-4 × 1.5-2.3 mm, base upcurved, cordate or hastate-auriculate, apex entire, narrowly obtuse to somewhat abruptly acuminate; column 0.4-0.6(-1) × 0.4-0.6(-1) mm; pollinia yellow. Capsules horizontal to erect, ellipsoid, 12 × 4 mm.
Flowering summer. Shaded mountain canyons; 2000 m; Ariz.; Mexico; n Central America.
Malaxis corymbosa grows in the Santa Rita, Huachuca, and Chiricahua mountains in Arizona. It differs from some of its close relatives in Mexico by having a more flattened and less fleshy lip that is less deeply concave proximal to anthers. Plants have 10-33 flowers open at one time and may produce a much larger number.