Description: Herb, to ca 1 m tall, branched, nodes swollen, glabrous. Leaves alternate to subopposite, ovate to ovate-lanceolate, 2.5–13 cm long, with 2 stipitate basal glands, glabrous; apex acuminate; base cuneate; margin serrate, teeth glandular-mucronate; lateral veins 7–12 on each side, petioles short or to 5 cm long. Inflorescences axillary or subterminal, racemose, 5–10-flowered; peduncles 7–15 cm; pedicels 1.5–2.3 cm, slender, bracts ovate-lanceolate, to 4 ,, long, apex mucronulate, glandular, caducous. Flowers yellow; lateral sepals 2, falcate, 2–4 mm long, apex aristate; lip bucciniform, 1.7 – 2 cm long, constricted into incurved filiform spur, long cornuted, 1.2 – 1.7 cm long. Upper petal orbicular, with long narrow curved ends; lateral united petals (wings), clawed; basal lobes oblong, ca 2 cm long, red spotted; distal lobes small, dolabriform. Stamens 5, connate into a ring surrounding ovary and stigma. Capsule clavate, ca 1.5 cm long; seeds glabrous or tuberculate. |
| Distribution: Distributed in India, Nepal, Bhutan, Myanmar, S China and NE Thailand, recorded from Phu Soi Dao, Loei provine, dry evergreen forest, on sandy soil, 900–1,000 m. |
