Trees or shrubs, evergreen, usually with essential oils-containing cavities in foliage, branchlets, and flowers. Stipules absent or small and caducous. Leaves opposite, occasionally alternate, occasionally ternate or pseudo-whorled; leaf blade with secondary veins pinnate or basal, often with intramarginal veins near margin, margin usually entire. Inflorescences axillary or terminal, cymose but variously arranged, 1- to many-flowered. Flowers bisexual, sometimes polygamous, actinomorphic. Hypanthium usually adnate to ovary and prolonged above it. Calyx lobes (3 or)4 or 5 or more, distinct or connate into a calyptra. Petals 4 or 5, sometimes absent, distinct or connate into a calyptra, sometimes coherent and pseudocalyptrate. Stamens usually numerous, in 1 to several whorls; filaments distinct or connate into 5 bundles opposite petals; anthers 2-celled, dorsifixed or basifixed, dehiscing longitudinally or rarely terminally; connectives usually terminating in 1 or more apical glands. Ovary inferior, semi-inferior, or very rarely superior, carpels 2 to more, locules 1 to many, pseudoseptum sometimes present, placentation usually axile but occasionally parietal; ovules 1 to several per locule. Style single; stigma single. Fruit a capsule, berry, drupaceous berry, or drupe, 1- to many-seeded. Seeds without endosperm or endosperm sparse and thin; testa cartilaginous or thinly membranous, sometimes absent; embryo straight or curved.
About 130 genera and 4500-5000 species: Mediterranean region, sub-Saharan Africa, Madagascar, tropical and temperate Asia, Australia, Pacific islands, tropical and South America; 10 genera (five introduced) and 121 species (50 endemic, 32 introduced treated here) in China.
The classification adopted here is that of Wilson et al. (Pl. Syst. Evol. 251: 3-19. 2005). The conventional classification of Myrtaceae sensu stricto in which the primary division is into two subfamilies based on the fruit being dry or fleshy (e.g., Niedenzu in Engler & Prantl, Nat. Pflanzenfam. 3(7): 57-105. 1893) results in an association of genera that is less natural than that proposed by Wilson et al.
Many Myrtaceae are cultivated garden ornamentals, street trees, or plantation trees. Some members of tribe Syzygieae are grown as fruit crops. In addition to the cultivated members of the family treated here, some others grown in China include Acca sellowiana (O. Berg) Burrett (Feijoa sellowiana (O. Berg) O. Berg), Myrtus communis Linnaeus, and Syncarpia glomulifera (Smith) Niedenzu.
Myrtus chinensis Loureiro is a synonym of Symplocos paniculata (Thunberg) Miquel in the Symplocaceae (see Fl. China 15: 252. 1996).
Chang Hung-ta & Miau Ru-hwai. 1984. Myrtaceae. In: Chen Chieh, ed., Fl. Reipubl. Popularis Sin. 53(1): 28-135.