Apiaceae

Herbs or shrubs. Leaves usually alternate; often highly dissected or compound, often basal; in the case of herbs the petiole often dilated into a sheathing base (Fig. 30). Stipules absent except in Centella. Flowers in simple or compound umbels or heads often subtended by an involucre of bracts, usually bisexual, regular. Sepals 5, small or sometimes obsolete. Petals 5, often bent inwards. Stamens 5, alternating with the petals. Ovary inferior, 1–2-locular, with 1 ovule per loculus; styles 2, free, swollen at the base into a fleshy epigynous nectiferous disc. Fruit a schizocarp, usually separating at maturity into two 1-seeded mericarps (except Actinotus) often suspended individually on the divided filiform central axis ( carpophore ); each carpel usually marked with longitudinal ribs and frequently by linear oil ducts or glands (vittae) which can be observed only in transverse section. 250 gen., mostly N. hemisphere.N.B. recent research has resulted in the transfer of the genera Hydrocotyle and Trachymene to the family Araliaceae