Citrus x aurantium L.

Rutaceae

Linnaeus, C. von (1753) Species Plantarum 2: 782. Type: Probably cultivated in Europe, Herb. Linn. 937.2, upper row of leaves.

Sweet Orange; Orange; Orange, Sweet

A small tree seldom exceeding 30 cm dbh.

Oil dots quite conspicuous, readily visible to the naked eye. Leaf blades about 6-10 x 3-5 cm. Petiole narrowly winged. Straight spines often present in the leaf axils.

Petals glabrous, about 16-18 x 6-7 mm, oil dots yellowish, large and conspicuous, readily visible to the naked eye on the outer surface of the petals. Stamens about 22-25, staminal filaments about 8-10 mm long. Disk at the base of the ovary, inside the whorl of staminal filaments.

Fruit depressed globular to +/- patelliform, about 7-11 cm diam., surface +/- smooth or slightly pitted. Pulp orange in colour, sweet.

First pair of leaves elliptic to +/- orbicular, margins entire, crenate or serrate. At the tenth leaf stage: petiole winged, oil dots clearly visible to the naked eye, leaf blade margins slightly toothed towards the apex. Seed germination time 10 to 34 days.

An introduced species originally from China and Vietnam, widely cultivated in Australia and now naturalised in NEQ. Altitudinal range from 400-800 m. Grows on farmland and in rain forest regrowth.

Citrus aurantium var. sinensis L., Species Plantarum 2: 782 (1753), Type: Probably cultivated in Europe, Herb. Linn. 937.2, upper row of leaves. Citrus sinensis (L.) Osbeck , Reise Ostindien China: 250 (1765).