Citron

This species is a parent with Citrus ×aurantium of C. ×limon and with ?C. hystrix of C. ×aurantiifolia.

The Buddha-hand Citron (佛手 fo shou), with separated segments ± surrounded by pericarp, is best treated as a cultivar, correctly Citrus medica ‘Fingered.’

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.

Himalaya (Garhwal to Sikkim), India, Burma, Indo-China, cultivated.

700-1200 m

Cultivated and sometimes naturalized. Guangxi, SW Guizhou, Hainan, Sichuan, E Xizang, Yunnan [native to NE India and possibly Myanmar].

Aurantium medicum (Linnaeus) M. Gómez; Citreum vulgare Tournefort ex Miller; Citrus alata (Yu. Tanaka) Tanaka; C. ×aurantium Linnaeus subvar. amilbed Engler; C. ×aurantium subvar. chakotra Engler; C. cedra Link; C. cedrata Rafinesque; C. fragrans Salisbury; ?C. kwangsiensis Hu; C. ×limon (Linnaeus) Osbeck var. digitata Risso; C. medica var. alata Yu. Tanaka; C. medica var. digitata Risso; C. medica var. ethrog Engler; C. medica f. monstrosa Guillaumin; C. medica var. proper J. D. Hooker; C. medica var. sarcodactylis (Hoola van Nooten) Swingle; C. odorata Roussel; C. sarcodactylis Hoola van Nooten; C. tuberosa Miller; Sarcodactilis helicteroides C. F. Gaertner.