Nigella seed. Coloured scanning electron micrograph (SEM) of a seed from a nigella flower (family Ranunculaceae). A seed contains an embryo (a fertilised ovule from which a new plant can grow), and a supply of food. The food is used either while the embryo grows within the developing seed, or during germination. Seed shapes and surface textures vary widely, affecting how they are dispersed from their parent plant. Seed dispersal methods include being carried by the wind, or water or on animal coats, or being eaten and deposited in animal droppings. Nigella seeds are used as a culinary spice. The plants are native to southern Europe, north Africa and southwest Asia. Magnification: x1000 when printed 10 centimetres wide.