Nautilocalyx Linden ex Hanst.

producing tubers; stems erect or decumbent, succulent, sometimes rooting at the nodes. Leaves opposite, elongate, equal or unequal in a pair; blades lanceo-late, elliptic or oblong, membranous or fleshy, often purplish below, the apex acute or acuminate, the base cuneate, often with a wing extending along the petiole. Inflorescences axillary of flowers in cymes, fascicles, or solitary, sub-tended by two or more leafy bracts. Flowers with an irregular calyx, the lobes unequal, green or colored; corolla white to yellow, usually with spots or lines of purple, tubular, broadened laterally, oblique in the calyx, with a short spur, limb 5-lobed, the lobes nearly equal, often large; stamens included, 4, filaments basally connate and adnate to the base of the corolla tube, the anthers apically joined in 2 pairs, dehiscing by a longitudinal slit; disc of a single posterior gland or of 2 opposite glands; ovary superior, the style included, the stigma bilobed. Fruit a bivalved capsule; seeds small, numerous, ellipsoid, striate, twisted.