Hydnoraceae

Abstract

Holoparasitic, fleshy, coriaceous plants, rich in tannins, with terete or angular, rhizome-like underground parts bearing series of vermiform outgrowths (haustorial roots) that connect the parasite to its host. Leafy structures missing. Flower buds developing underground, emerging at anthesis. Flowers actinomorphic, usually bisexual (functionally unisexual in Hydnora esculenta), with a more or less cylindrical flower tube, often swollen at the base, apically with 2–5 valvate, fleshy lobes. Androecium synandrial, rarely with filaments, with numerous pollen sacs, in Hydnora staminal structures forming a wavy ring with distinct lobes opposite the perigon lobes, in Prosopanche inserted opposite the perigon lobes, united into a conical cap, alternating with fleshy staminodia deeper in the tube. Ovary inferior, usually subterraneous, with a flat, sessile stigma, 3–4(−5) carpellate, unilocular, with numerous placentas, as parietal lamellae (Prosopanche) or pendulous from the apex of the ovary (Hydnora). Ovules numerous, orthotropous, tenuinucellate, unitegmic. Fruit an underground berry, with a thick, leathery wall. Seeds numerous, globular or ovate, very small, with a hard, thick testa, embedded in a fleshy or gelatinous, edible pulp which is rich in starch. Embryo small, surrounded by endosperm and perisperm.