Lemon (scientific name: Citrus limon (L.) Burm. f.), rutaceae citrus plants, lemon is also known as lime fruit, lemon, Yimu fruit, etc. Small trees, branches less prickly or nearly unprickly, young leaves and flower buds dark purplish red, leaves thick papery, ovate or elliptic. Flowers simple axillary or less fascicled. Fruit elliptic or ovate, rind thick, usually rough, lemon yellow, juice acid to very sour, seeds small, ovate, apical; Seed coat smooth, cotyledon opalescent, usually simple or polyembryonal. Flowering period from April to May, fruit period from September to November.