Trees or shrubs, rarely herbs; leaves, flowers and fruits usually bearing numerous oil glands. Leaves opposite or alternate, simple or compound, exstipulate. Monoecious or dioecious; flowers actinomorphic, unisexual or bisexual, in axillary or terminal racemes, corymbs or panicles, sometimes solitary. Calyx 4-5-lobed. Petals 4-5, free, valvate or limbricate. Stamens 4-5 or 8-10 or more (Aegle and Citrus); filaments free or connate; in female flowers stamens reduced to staminodes. Ovary superior, of 4-5 or more free or connate carpels; in male flowers ovary reduced to pistillode. Fruit a capsule, cluster of follicles, berry or drupe; seeds solitary or few in each cell.
Small trees, branches usually armed with straight spines. Leaves simple; petioles winged and articulated with lamina. Flowers bisexual, rarely unisexual, solitary or in short axillary racemes. Calyx 4 - 5 lobed. Petals 4 - 5, free, gland-dotted, imbricate. Stamens numerous, free or united at base. Ovary globose or cylindrical; style distinct or tapering into ovary; stigma capitate. Fruit a berry, with segments filled with stalked pulp vesicles and bearing seeds at inner angles, the whole surrounded by gland-dotted peel, green, often turning yellow or orange at maturity.
Tree 3m; twigs mostly spineless. Leaves ovate-lanceolate, 5 - 7 x 2 - 3cm, acute but with blunt tip, base cuneate, margin obscurely crenate; petiole 0.7cm, narrowly winged. Flowers solitary or in axillary clusters, similar to those of C.sinesis. Fruit globose or depressed-globose, 5 - 10cm diameter; peel thin, loosely attached, easily separating from 8 - 9 segments, bright orange or scarlet orange.