This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Annual glabrous herbs, with thin, pinnately divided or pinnately decompound leaves, and compound umbels of white flowers. Involucre none. Involucels of a few narrow bracts. Fruit subglobose, hard, scarcely flattened, not constricted at the commissure, its ribs slender. Stylopodium conic, the styles slender. Calyx-teeth ovate, acute. Oil-tubes solitary in the intervals, a few on the commissural side. [Ancient Latin name.]
Two species, of the warmer parts of the Old World, the following typical.
Coriandrum sativum L. Sp. Pl 256. 1753.
Erect, 2° high or less. Lower leaves pinnately divided, their segments broad, ovate to obovate, variously toothed and cleft; upper leaves pinnately decompound, with narrowly linear segments; flowering umbels l'-2' broad, the rays slender; pedicels 1"-2" long; involucel-bracts deciduous; fruit about 2" long and thick, its acutish ribs narrower than the intervals between them.
Bifora americÓna (DC.) S. Wats., of the southwest, an annual with finely dissected leaves, the characteristic fruit composed of two nearly separated subglobose carpels, has been recorded from Missouri, but is not definitely known to grow north of Arkansas.
Bifora radians Bieb., of southern Europe, with larger wrinkled fruit, has been collected on ballast and waste grounds in Rhode Island and Pennsylvania.