Rosaceae

Woody or herbaceous plants. Leaves usually spirally arranged, sometimes distichous, rarely opposite (not in Malesia), simple or compound. Stipules on the twig or on the base of the petiole, free or adnate to petiole, rarely absent Inflorescences various. Flowers usually bisexual and actinomorphic. Hypanthium (‘calyx tube’ of many authors) usually very distinct, from saucer-shaped to tubular or campanulate, the sepals, petals, and stamens inserted on its rim, its inside usually lined by a nectariferous disk. Sepals usually 5, free, in some tribes an epicalyx also present. Petals usually 5, free, from large and showy to small and not or hardly distinct from sepals, in some genera/species absent. Stamens usually numerous, but sometimes the number distinctly related to the number of perianth leaves, filaments free, anthers bilocular, dehiscing longitudinally. Pistil(s) 1 to many, free or variously connate with each other and/or with the hypanthium, ovary(ies) superior to inferior, style(s) present, ovule(s) 1 to several (often 2) per locule, anatropous, ascending or pendulous. Fruits various, fleshy or dry, dehiscent or not. Seed(s) 1 to several, without or with scanty endosperm, cotyledons fleshy or flat. Distribution — A large family with worldwide distribution, including more than 3000 species in c. 100 genera. Almost all genera which are represented in Malesia have their actual centre of distribution in temperate to subtropical regions on the Northern Hemisphere. Some of those are large or medium large genera with only one or two species in Malesia (Rosa, Alchemilla, Eriobotrya), others have a more or less distinct sub-centre in the Malesian region ( Prunus, Rubus, Potentilla). Exceptional is Acaena, a genus with a Southern Hemisphere distribution, of which one species also occurs in New Guinea.