Myristicaceae R.Br.

Scientific Description

Common name. Nutmeg Family.

Habit and leaf form. Trees; evergreen; with coloured juice (typically with red sap); bearing essential oils. Mesophytic. Leaves alternate; spiral to distichous; leathery; petiolate; non-sheathing; gland-dotted (often), or not gland-dotted; aromatic (often), or without marked odour; simple. Leaf blades entire; pinnately veined; cross-venulate. Leaves without stipules. Leaf blade margins entire. Leaves without a persistent basal meristem. Vernation conduplicate. Stem anatomy. Nodes bilacunar (but with three traces, according to Lammers et al. 1986), or unilacunar. Secondary thickening developing from a conventional cambial ring.

Reproductive type, pollination. Fertile flowers functionally male and functionally female, or functionally male, or functionally female. Unisexual flowers present. Plants monoecious, or dioecious. Female flowers without staminodes. Male flowers without pistillodes.

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; in cymes, in fascicles, in racemes, and in heads. The terminal inflorescence unit cymose, or racemose. Inflorescences axillary. Flowers bracteate (the bract usually solitary, small); small; usually 3 merous; cyclic. Perianth sepaline; (2–)3(–5); 1 -whorled; joined. Calyx (the perianth being thus interpreted) (2–)3(–5); 1 -whorled; gamosepalous; blunt-lobed; valvate. Fertile stamens present, or absent (female flowers). Androecium (2–)3–30. Androecial members branched, or unbranched; free of the perianth; coherent; 1 - adelphous (the filaments united into a column); 1 -whorled. Androecium exclusively of fertile stamens. Stamens (2–)3–30; isomerous with the perianth to polystemonous. Anthers cohering (laterally connate), or separate from one another; dehiscing via longitudinal slits; extrorse; tetrasporangiate. Pollen shed as single grains. Fertile gynoecium present, or absent (in male flowers). Gynoecium 1 carpelled. The pistil 1 celled. Carpels reduced in number relative to the perianth. Gynoecium monomerous; of one carpel; superior. Carpel incompletely closed; non-stylate, or stylate (subsessile); apically stigmatic; 1 ovuled. Placentation basal. Ovules arillate; anatropous.

Fruit and seed features. Fruit fleshy to non-fleshy (fleshy to leathery). The fruiting carpel usually dehiscent; a legume (i.e. from a single carpel, dehiscing along both sutures—or a ‘dehiscent berry’!). Fruit 1 seeded. Seeds endospermic. Endosperm ruminate; usually oily. Embryo well differentiated (very small). Cotyledons 2 (sometimes basally connate). Embryo achlorophyllous (2/4); straight. Seedling. Germination cryptocotylar.

Geography, cytology, number of species. World distribution: pantropical. X = 9, 21, 25. 300 species.

Economic uses, etc. Myristica fragrans supplies the spices nutmeg (the seed), and mace (dried arils).