This section is from the book "Culinary Herbs", by M. G. Kains. Also available from Amazon: Culinary Herbs, Their Cultivation, Harvesting, Curing and Uses.
Fennel Flower (Nigella sativa, Linn.), an Asiatic annual, belonging to the Ranunculaceae, grown to a limited extent in southern Europe, but scarcely known in America. Among the Romans it was esteemed in cookery, hence one of its common names, Roman coriander. The plant has a rather stiff, erect, branching stem, bears deeply cut grayish-green leaves and terminal grayish-blue flowers, which precede odd, toothed, seed vessels filled with small, triangular, black, highly aromatic seeds. For garden use the seed is sown in spring after the ground gets warm. The drills may be 15 to 18 inches apart and the plants thinned to 10 or 12 inches asunder. No special attention is necessary until midsummer, when the seed ripens. These are easily threshed and cleaned. After drying they should be stored in sacks in a cool, dry place. They are used just as they are or like dill in cookery.