Dilleniaceae

Trees, shrubs or lianes, rarely perennial herbs. Leaves alternate, simple (in ours), entire or variously toothed, with prominent parallel lateral nerves. Flowers bisexual or unisexual, borne in cymes, racemes or panicles. Sepals 5, free. Petals (2-)5(-6), often showy. Stamens many. Carpels 3-5. Fruits dehiscent or berry-like. Seeds usually with a created or laciniate aril.

Comment: Placing the family has proved difficult. A major objective of the first meeting of the Angiosperm Phylogeny Group (1998) was to reduce to number of Eudicot orders to around 40, largely to facilitate filing of herbarium material. Orders comprising just one or two families should be merged with larger orders. In the case of Dilleniaceae this meant placing the family in the Caryophyllales, a somewhat awkward fit. In such cases the practice of bracketing was allowed: Order Caryophyllales (Dilleniales), but described as “unplaced”. In subsequent meetings of APG the placement of the family has remained unresolved. Dilleniaceae is one of the oldest of the Eudicots, having emerged in the mid-Cretaceous about 115 million years ago, although the “crown group” diverged much later, 52 million years ago (Wikipedia). As such it links the Eudicots with the more primitive Dicots. Eudicots – Order Caryophyllales (Dilleniales) – Family Dilleniaceae.

Worldwide: C. 12 genera and 300 species, tropical and subtropical, especially Australasia.

Zimbabwe: 2 cultivated genera and 2 cultivated taxa.