Annonaceae Juss.

Scientific Description

Common name. Custard-Apple Family.

Habit and leaf form. Trees, or shrubs, or lianas; evergreen; bearing essential oils; resinous, or not resinous. Self supporting, or climbing; when climbing, scrambling, or stem twiners, or petiole twiners. Leaves alternate; distichous; non-sheathing; gland-dotted, or not gland-dotted; aromatic, or without marked odour; simple. Leaf blades entire; pinnately veined; cross-venulate. Leaves without stipules. Leaf blade margins entire. Domatia recorded (in 3 genera); represented by pockets (usually), or hair tufts (in 1/12 species). Stem anatomy. Nodes unilacunar, or bilacunar (according to Lammers et al 1986). Secondary thickening developing from a conventional cambial ring.

Reproductive type, pollination. Fertile flowers hermaphrodite, or functionally male and functionally female, or functionally male, or functionally female. Unisexual flowers present, or absent. Plants hermaphrodite, or monoecious (rarely), or dioecious.

Inflorescence and flower features. Flowers solitary, or aggregated in ‘inflorescences’. The terminal inflorescence unit racemose. Flowers regular; cyclic, or partially acyclic. Sometimes the androecium acyclic (spiralled). Free hypanthium absent. Hypogynous disk present. Perianth with distinct calyx and corolla (usually P3+3+3, with the outer one or two whorls sepaloid); usually 9; usually 3 -whorled; isomerous. Calyx 3, or 6; usually 2 -whorled; polysepalous; valvate, or open in bud. Corolla 3; 1–2 -whorled; polypetalous; imbricate, or valvate. Fertile stamens present, or absent (rarely). Androecium usually 25–100 (i.e. ‘many’). Androecial sequence determinable, or not determinable. Androecial members when many, maturing centripetally; free of the perianth; all equal; free of one another; rarely 3 -whorled, or 6 -whorled (otherwise spiralled). Androecium exclusively of fertile stamens (usually), or including staminodes (e.g. in Uvaria spp., where the outer members may be imperfect). Staminodes non-petaloid. Stamens 25–100 (‘many’). Anthers adnate; non-versatile; dehiscing via longitudinal slits, or dehiscing by longitudinal valves; extrorse; tetrasporangiate; appendaged (via expansion of the connective). Pollen shed in aggregates (5 genera), or shed as single grains; when aggregated, in tetrads (usually), or in polyads (octads in Trigynaea). Fertile gynoecium present, or absent (rarely). Gynoecium usually 10–100 carpelled (or more — i.e. ‘many’). The pistil when syncarpous, 1–15 celled. Gynoecium apocarpous (usually), or syncarpous (rarely); eu-apocarpous (the carpels spiralled or cyclic), or synstylovarious to eu-syncarpous (e.g. Monodora); superior. Carpel 1–10 ovuled. Placentation of free carpels basal. Ovary unilocular, or plurilocular; when syncarpous 1 locular, or 2–15 locular (or more — i.e. ‘multilocular’). Stigmas wet type; papillate; Group III type. Placentation when unilocular parietal, or basal; when plurilocular basal. Ovules in the single cavity when unilocular, 1–50; 10–50 per locule (i.e. ‘many’); ascending; apotropous; with ventral raphe; arillate, or non-arillate; anatropous.

Fruit and seed features. Fruit fleshy; an aggregate (commonly an aggregate of berries). The fruiting carpels coalescing into a secondary syncarp, or not coalescing. The fruiting carpel indehiscent; baccate. Seeds endospermic. Endosperm ruminate (by contrast with Magnoliaceae); oily. Seeds with amyloid. Embryo achlorophyllous (4/5). Seedling. Germination phanerocotylar, or cryptocotylar.

Geography, cytology, number of species. World distribution: widespread, especially Old World. X = 7, 8, 9. 1200 species.

Economic uses, etc. Important commercial fruits from Annona spp. (atemoya, cherimoya, custard-apple, ilarma, sugar-apple, sweet sop, sour sop), Artabotrys.