A glabrous, twining, perennial herb or undershrub; branches slender, terete, sap milky; leaves opposite, linear-lanceolate, acute, thin; petioles slender; flowers large in axillary, lax, racemose or umbelliform cymes; pedicels filiform; bracts deciduous; calyx small, lobes-5, linear, imbricate; corolla white or pink with purple veins; overlapping to right in bud, ciliate, acute, recurved; corona 2 seriate; coralline annular, pubescent at the base of corolla; inner one papilose of 5, erect, ovate or lanceolate scales, attached to the staminal column, staminal scales inserted at the base of corolla-tube; filaments short, connate; anthers erect, tipped with an appendage; pollinia solitary in each anther cell, oblong, compressed, pendulous, waxy; stigma depressed or subconvex; follicles thick, oblique or curved, narrowly winged, 4-7 cm long; seeds very numerous, ovoid; coma silky, dull white.