Umbelliferae

Annual or perennial herbs, never woody shrubs (in Malaysia). Stems often furrowed and with soft pith. Leaves alternate along the stems, often also in rosettes; petiole usually with a sheath, sometimes with stipules at the base; lamina usually much divided, sometimes entire. Flowers polygamous, in simple or compound umbels, sometimes in heads, terminal or leaf-opposed, beneath with or without involucres and involucels. Calyx teeth 5, often obsolete. Petals 5, alternate with the calyx teeth, equal or outer ones of the inflorescence enlarged, entire or more or less divided, often with inflexed tips, inserted below the epigynous disk. Stamens alternate with the petals, similarly inserted. Disk 2-lobed, free from the styles or confluent with their thickened base, forming a stylopodium. Ovary inferior; styles 2. Fruits with 2 one-seeded mericarps, connected by a narrow or broad junction (commissure) in fruit separating, leaving sometimes a persistent axis ( carpophore) either entire or splitting into 2 halves; mericarps with 5 longitudinal ribs, 1 dorsal rib at the back of the mericarp, 2 lateral ribs at the commissure; 2 intermediate ribs between the dorsal and the lateral ones; sometimes with secondary ribs between the primary ones, these without fascicular bundles; often vittae in the ridges between the ribs or under the secondary ribs, and in the commissure, seldom under the primary ribs. Distr. Numerous genera and species, all over the world. The representatives native in Malaysia belong geographically to five types. (1) Ubiquitous genera ( Hydrocotyle, Centella, Oenanthe); one species, Hydrocotyle vulgaris, shows a remarkable disjunction, occurring in Europe & N. Africa and also in New Guinea, Australia and the Marshall Islands. (2) Western elements are Sanicula (wide-spread in the N. hemisphere but absent from New Guinea and Australia), Heracleum and Pimpinella; though some spp. are endemic their close relatives are found in SE. Asia. (3) A distinctly N. element is the Japano-Formosan Peucedanum japonicum in the islands N. of Luzon. (4) A distinct Australian element is Trachymene which centers in Australia and occurs also in New Caledonia and Fiji; this genus shows a relatively rich secondary centre in East Malaysia; another Australian alliance is found in ubiquitous Eryngium of which the only native Malaysian species hitherto known is allied to Australian spp. (5) A distinct Subantarcticdistributed genus is Oreomyrrhis which centers in New Guinea by 4 spp.; one of these occurs from Kinabalu to Australia, New Zealand to Andine South America as far as Mexico; a marked instance of the ancient alpine-Papuan South Pacific plant refuge (v. ST.).