Citrus sinensis

Family

Rutaceae

Botanical Name

Citrus sinensis (L.) Osbeck

Osbeck, P (1765) Reise Ostindien China: 250. Type: ?.

Synonyms

Citrus aurantium (var.) sinensis L., Species Plantarum 2: 782(1753), Type: Europe (cultivated); originally from China, Indo-China & other parts of SE Asia.

Common name

Sweet Orange; Orange; Orange, Sweet

Weed

Stem

A small tree seldom exceeding 30 cm dbh.

Leaves

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.

Flowers

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

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

Seedlings

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.

Distribution and Ecology

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