Annual or perennial herbs with taproot (sometimes fleshy), rhizomes or stolons. Leaves basally rosetted or cauline, simple or compound, alternate or rarely opposite or whorled; petiole often sheathing at base, rarely with stipules. Inflorescence terminal or axillary, either a simple or compound umbel, or a head reduced to 1–few flowers, with involucral bracts and bracteoles. Flowers actinomorphic, bisexual or unisexual and the plants monoecious, polygamous or rarely dioecious; sepals and petals 5 or either (sometimes both) absent; stamens 5, anthers 2-locular, dehiscing by longitudinal slits; nectary a disk (stylopodium) at base of swollen styles; ovary inferior, 2(rarely 1)-locular, ovule 1 per locule, pendulous, styles 2, free, usually 2-lobed. Fruit dry, indehiscent, usually separating at maturity from the central axis (carpophore) into 2 indehiscent mericarps; mericarps often flattened laterally or dorsally, with or without longitudinal ribs.
Over 250 genera and 3000 species, world-wide but chiefly in temperate regions; 48 genera (12 endemic) and c. 200 species in Australia. The family may also be known by the alternative name Umbelliferae.
Many species of Apiaceae are economically important and widely cultivated, including Apium graveolens L. (Celery), Daucus carota L.(Carrot), Foeniculum vulgare Mill. (Fennel), Anethum graveolens L. (Dill), Petroselinum crispum (Mill.) Nyman ex A.W. Hill (Parsley), Coriandrum sativum L. (Coriander), Carum carvi L. (Caraway), Cuminum cyminum L. (Cumin) and Pimpinella anisum L. (Anise). However, most species are poisonous and some, e.g. Conium maculatum L. (Hemlock), have been actively used as poisons.
Hydrocotyle and Trachymene have traditionally been placed in Apiaceae. However, following molecular studies of Apiaceae/Araliaceae the placement of these two genera has been revised, and they are now included in Araliaceae. Hydrocotyle and Trachymene have morphological affinities with both families, but there are no demonstrated shared unique (apomorphic) characters to link these two genera with other members of Araliaceae. Hydrocotyle and Trachymene are not readily distinguished from members of Apiaceae. As such, they remain in leads to Apiaceae in the key to dicotyledon families and have been included in the key to genera of both Apiaceae and Araliaceae.
Chandler, G.T.; Plunkett, G.M. (2004). Evolution in Apiales: nuclear and chloroplast markers together in (almost) perfect harmony, Botanical Journal of the Linnean Society 144: 123-147.
Nicolas, A.N.; Plunkett, G.M. (2009). The demise of subfamily Hydrocotyloideae (Apiaceae) and the re-alignment of its genera across the entire order Apiales, Molecular Phylogenetics and Evolution 53: 134–151.