A large family, widely distributed, not abundant in the tropics; usually strong-smelling herbs, remarkable for their aromatic oil, mostly with hollow, grooved stems; leaves alternate, compound, generally deeply cut, leaf-stalks often broadened at base; flowers very small, usually in broad, flat-topped clusters, generally with bracts; calyx usually a five-toothed rim around the top of the ovary; petals five, small, usually with tips curled in, inserted on a disk, which crowns the ovary and surrounds the base of the styles; stamens five, with threadlike filaments and swinging anthers, also on the disk; ovary two-celled, inferior, with two threadlike styles; fruit two, dry, seedlike bodies, when ripe separating from each other, and usually suspended from the summit of a slender axis, each body marked with ribs, usually with oil-tubes between the ribs. The examination of these oil-tubes in mature fruits, with a microscope, is necessary to determine most of the genera and species, so description of genera is omitted here, and botanists have added to the difficulties of the amateur by giving almost every genus more than one name. The flowers are much alike, yet the leaves often differ very much in the same genus. Many kinds are poisonous, although others, such as Parsley, Carrot, and Parsnip, are valuable food plants.