Nigella sativa is an annual flowering plant that grows to 20 to 30cm (8 to 12in) tall, is native to Asia and the Middle East. The flowers of this plant are very delicate and have five petals about 2.5cm (1in) wide, usually white they are occasionally tinted with pale blue veins and appear between June and September.
They yield a seed capsule with five compartments each topped by a spike. The compartments open when dried to disperse the seeds. The seeds are small, matte-black grains with a rough surface and an oily white interior. They are roughly triangulate, 2mm in length and look similar to onion seeds.