Pterygodium cooperi Rolfe

Plants slender, to 290 mm; leaves 2-4, basal and cauline, to 160 x 50 mm, basal leaf large, broadly ovate to ovate-oblong, subacute, cauline leaves lanceolate to elliptic. Inflorescences lax, to 100 mm long, 5-numerous-flowered; bracts lanceolate, acute, deflexed, to 15 x 5 mm. Flowers c. 20 x 15 mm, with pale green to purplish-green sepals, white and green petals, lip and appendage white; ovaries c. 12 mm long. Median sepal elliptic, broadly acute, 6-8 x 2-4 mm, adnate to the petals; lateral sepals reflexed, oblique, subacute, concave basally, 7-9 x 4-5 mm. Petals broad, 6-9 x 6-11 mm. Lip deltate, acute, 3-5 mm long, with 2 stout, subacute, deflexed side lobes; appendage obdeltate, with a longitudinal ridge anteriorly, c. 4-5 x 5 mm. Rostellum c. 2 mm tall, arms c. 2 mm long.