Citrus aurantiifolia (Christm.) Swingle

Shrubs or trees, 2-8 m high, usually armed with numerous axillary spines 5-17 mm long. Leaflets oblong elliptic to ovate, acute to obtuse and abruptly acuminate and somewhat emarginate apically, rounded basally, the margins crenulate and somewhat revolute, 37-134 mm long, 17-62 mm wide; petioles oblanceolate winged, 5-28 mm long, 2-9 mm wide, articulated with the leaflet. Flowers with the peduncles 3-5 mm long; calyx shallowly 4-5 lobed, fleshy, puberulent, glandular punctate, ca. 2 mm high, the lobes broadly triangular, to 1 mm long; petals 4-5, white, oblong lanceolate, 11-14 mm long, ca. 4 mm wide; stamens 20-25, the filaments 4-6 mm long, connate into a number of groups, the anthers linear sagittate, 2-3 mm long; intrastaminal disc fleshy, ca. 1 mm high; ovary obovoid, depressed at the base of the style and sharply distinct from it, 2-3 mm high, the style 2-3 mm long, soon deciduous, the stigma subglobose, depressed apically, ca. 2 mm in diameter. Fruits ellipsoidal, mammillate apically, green to yellow, 3.5-6.0 cm in diameter, acid, the core solid.

A tropical plant. They need a warm climate and are most common in coastal regions in the lowland tropics. They grow from sea level to 2200 m altitude in Papua New Guinea. They suit humid areas and can survive in poor soils. Light to medium well drained soils are best. It is drought and frost tender. In Hobart Botanical gardens. It grows in Nepal to about 1800 m altitude. It can grow in alkaline soil. It suits hardiness zones 11-12.

They are mainly used for juice and drinks. They are preserved in syrup and made into jam, jelly and marmalade. They can be used in pickles. It is used as a coagulant in the manufacture of soft cheeses. The chopped peel can be made into a sweetmeat with milk and coconut. The minced leaves are eaten with roast meat. They are also added to soups.

They are often grown from seed but are better if grafted. Plants can be grown by cuttings. A spacing of 4-5 metres is suitable. When grown from seed, several shoots may develop from the one seed, which means the seedlings may be identical to the parent.