Nelumbonaceae

Abstract

Herbaceous aquatic perennial developing horizontal rhizomes and tubers. Roots adventitious, produced at nodes. Phyllomes distributed in sets of three along the rhizome (one foliage leaf, two fleshy cataphylls). Foliage leaves simple, peltate, emergent and floating, producing latex. Petioles of emergent leaves terete, to 2 m in length, bearing prickles. Blades concave, large, 10–100 cm in diameter, orbiculate, entire, bluish green adaxially and remarkably water-repellent. Flowers solitary, perfect, actinomorphic, hypogynous, 10–100 cm across, pink to white or yellowish, elevated above water on terete peduncles up to 2 m in length; floral phyllotaxy spiral; perianth caducous; sepals 2–5; petals ca. 20–30; stamens 200–300, filaments elongate, bearing four introrsely to latrorsely dehiscent anthers, terminated by claw-like, thermogenic appendage. Gynoecium of 2–30 free carpels embedded in the truncate surface of the enlarged obconical, spongy receptacle; each carpel with a distinct, circular stigma with a central canal into the ovary; ovule solitary, ventral-apical, pendulous, anatropous, bitegmic-crassinucellar. Fruits globose or elongate ovoid, with the carpel wall adnate to the testa forming a hard-walled nut, filled by the edible embryo, embedded in an enlarged, dry, sclerified receptacle. Embryo with two thick and fleshy cotyledons surrounding a green plumule, the latter enclosed by a delicate stipule-like sheath. Radicle non-functional. Endosperm minute, helobial, lacking perisperm; seeds exalbuminous.