Citrus fruits include oranges, lemons, limes ,grapefruits, tangerines and pomelos. Citrus is the common term for plants of the family, Rutaceae. These plants are large shrubs or small to moderate-sized trees, reaching 5–15 m tall, with spiny shoots and alternately arranged evergreen leaves. The flowers are solitary or in small corymbs, each flower 2–4 cm in diameter, with five or sometimes four white petals and numerous stamens.
Citrus fruits are notable for their fragrance, partly due to flavonoids and limonoids contained in the rind, and most are rich in juice. The juice contains a high quantity of citric acid giving them their characteristic sharp flavour. Citrus trees hybridize very readily, depending on the pollen source. Most commercial citrus orchards use trees produced by grafting the desired fruiting cultivars onto rootstocks selected for disease resistance and hardiness.