Annonaceae – Taxonomy, Genera
qiazhan English name: Annonaceae
Sub Title:
Annonaceae, the custard apple, or annona, family, the largest family of the magnolia order (Magnoliales) with 110 genera and about 2,430 species. The family consists of trees, shrubs, and woody climbers found mainly in the tropics, although a few species extend into temperate regions. Many species are valuable for their large pulpy fruits, some are useful for their timber, and others are prized as ornamentals. Bark, leaves, and roots of several species are important in folk medicine, and others are important sources of perfume and spice.
Members of the family Annonaceae have simple leaves with smooth margins that are alternately arranged in two rows along the stems. The radially symmetrical flowers are usually bisexual. In most species the three sepals are united at the base. There are six brown, yellow, or greenish petals, many stamens in a spiral, and many pistils, each with a one-chambered ovary containing many ovules. The fruit is a berry. Flowers in some species are borne directly on large branches or on the trunk (cauliflorous). The leaves and wood are often fragrant.
Major genera and species
The genera Uvaria, with about 200 species; Xylopia, with about 180 species; Guatteria, with 177 species; and Annona, with 170 species, are the largest of the family. Other genera include Goniothalamus, Artabotrys, Duguetia, Monanthotaxis, Polyalthia, Miliusa, Fissistigma, Orophea, Pseuduvaria, Mitrephora, Unonopsis, Isolona, and Piptostigma.
The large genus Annona is one of the most economically important genera of the family. Several species bear highly prized fruits. The alligator apple (A. glabra) of tropical America and western Africa, also known as pond apple and corkwood, is a 12-metre (40-foot) evergreen tree with 18-cm- (7-inch-) long oval leaves and fragrant yellowish flowers. It bears smooth, gnarled, yellowish fruits, 5–10 cm long, which are edible but of poor flavour. Its roots are used to make bottle corks and fishing floats and as rootstock for grafting less hardy species of Annona.
The custard apple (A. reticulata), a small tropical American tree, gives the family one of its common names. Also known as bullock’s-heart for its globose shape, it has fruits with creamy white, sweetish, custardlike flesh. Cherimoya (A. cherimola), soursop (A. muricata), and sweetsop (A. squamosa) are related plants with similar edible fruits.
A South American tree, Porcelia saffordiana, bears immense fruits sometimes weighing 18 kg (40 pounds) or more.
The genus Monoon comprises some 60 species. A handsome ornamental of the family is the weeping form of the mast tree (M. longifolium, formerly Polyalthia longifolia variety pendula), of Sri Lanka. Its shining, brilliant green, willowy, wavy-edged leaves hang from pendant branches that almost clasp the tall straight trunk. The leaves are used as temple decorations in India.
The American pawpaw (Asimina triloba), native to the eastern United States, bears sweet edible fruits with a custardlike texture.
