Ichang papeda

A small thorny tree or bush, about 2-4m high, with angular branches when young, and strong, pointed thorns about 1.5-2cm long. On flower-bearing branches the thorns are smaller or absent. The leaves are narrow, about 4-5 times longer than they are wide, with a large petiole, winged and oblong or obovoid in shape, with a rounded tip and pointed base. The leaves are oval with acuminate tip and rounded base, often smaller in area than the wings. The flowers are arranged singly at the axillary point of the leaf, quite small and white with 20 stamens, deciduous stylus almost as large as the ovary which consists of 7-9 locules with numerous ovules. The fruit is small, rounded, 3.5-5cm in diameter with wrinkled skin 3-4mm thick, light green when ripe. The seeds are large, very thick and monoembryonic. This plant grows wild in central and south-west China and is one of the most cold-hardy evergreen species of the aurantioiddeae subfamily.
Hybrids of citrus ichangensis x citrus aurantium have been obtained at the Istituto Sperimentale di Agrumicoltura in Acireale, and are much more vigorous than the two parent species.