(Citrus medica), a plant of the family Rutaceae. The citron is a shrub or small tree reaching 3 m in height. The branches have single axillary spines measuring 3–5 cm long. The large, ellipticovate, flat leaves have short winged petioles. The upper leaves are purple on growing shoots and dark green on mature shoots. The large bisexual or functionally male flowers are white with a reddish tinge; they are solitary or in inflorescences. The oblong, oval, or turban-shaped fruit is large, measuring 12–14 cm long and 8–10 cm across. The rough, warty, wrinkled (rarely smooth) rind is very thick (2–5 cm); it is lemon yellow or, sometimes, orange in coloration. It has a bitter or sweet taste and a pleasant aroma. The firm pulp is sour or tart; it contains citric acid.
The citron is native to India and southern China. Unknown in wild form, it is cultivated in many countries with a subtropical or tropical climate. The crop was brought to the Black Sea coast of the Caucasus at the end of the 17th century, but its cultivation did not spread because the plant was not frost-resistant. The citron is raised in botanical gardens and plant collections in humid subtropical zones of the Georgian SSR. Citron plants freeze at temperatures of –3°C and –4°C. The fruits are used to prepare preserves, and the rind is candied. In India and other subtropical countries seedlings are used as rootstocks for other citrus crops and, less commonly, as ornamentals. The leaves, floral parts, and rind yield essential oil.
A. D. ALEKSANDROV