Citrus medica L.

Shrubs or small trees. Branches, leaf buds, and flower buds purplish when young. Branches with ca. 4 cm spines. Leaves simple or rarely 1-foliolate; petiole short, not winged; leaf blade elliptic to ovate-elliptic, 6-12 × 3-6 cm or larger, margin serrate, apex rounded, obtuse, or rarely mucronate. Inflorescences axillary, ca. 12-flowered or sometimes flowers solitary. Flowers bisexual or sometimes male by ± complete abortion of pistil. Petals 5, 1.5-2 cm. Stamens 30-50. Ovary cylindric; style long and thick; stigma clavate. Fruit pale yellow, elliptic to subglobose, to 2 kg, surface coarse; pericarp white to pale yellow and soft within, thicker than sarcocarp, removed with difficulty; sarcocarp with 10-15 segments, colorless, nearly pellucid to pale milky yellow, acidic to slightly sweet, fragrant. Seeds small; seed coat smooth; embryo(s) solitary to several; cotyledons milky white. Fl. Apr-May, fr. Oct-Nov. 2n = 18, 20.

A subtropical plant. It prefers rich, moist soils. The soils need to be well aerated and not waterlogged. They should be in a protected sunny position. They are drought and frost tender. It needs temperatures between 12°C and 35°C. It suits hardiness zones 9-11. In Yunnan.

The thick layer of inner white skin is used as candied peel. It is also added to salads and used in fruit cakes. The juice of some kinds is used for drinks. The fruit are used for marmalade. Caution: The fruit contain coumarin that with sunlight can cause dermatitis in some people.

Trees can be grown by seed, cuttings or grafting. Seed should germinate in 21 days. Cuttings of 2-4 year old branches are used. Air-layering can be used. A spacing of 5-7 m is suitable.