《中国植物志》|| 芸香科 RUTACEAE ||柑橘亚属 Subgen. Citrus ||柠檬 Citrus limon (L.) Burm.f.

9.柠檬 洋柠檬、西柠檬 图版49:7-8
Citrus limon (L.) Burm. f. Fl. Ind. 173. 1768; Swingle in Webb. et Batc. Citrus Indust. 1: 398. 1943, et in Reuth. et al. l. c. rev. ed. 1: 372. 1967; Tanaka, Sp. Probl. Citrus 114. 1954;广州植物志430. 图227. 1956.——C. medica var. limon L. Sp. Pl. 2: 782. 1753; Engl. in Nat. Pflanzenfam. 3(4): 201. 1896 "Limonum"——C. limonelloides Hayata, Icon. Pl. Form. 8:16. 1919.——C. limonia auct. non Osb.: Engl. l. c. 19a: 335. 1913.
小乔木。枝少刺或近于无刺，嫩叶及花芽暗紫红色，翼叶宽或狭，或仅具痕迹，叶片厚纸质，卵形或椭圆形，长8-14厘米，宽4-6厘米，顶部通常短尖，边缘有明显钝裂齿。单花腋生或少花簇生；花萼杯状，4-5浅齿裂；花瓣长1.5-2厘米，外面淡紫红色，内面白色；常有单性花，即雄蕊发育，雌蕊退化；雄蕊20-25枚或更多；子房近筒状或桶状，顶部略狭，柱头头状。果椭圆形或卵形，两端狭，顶部通常较狭长并有乳头状突尖，果皮厚，通常粗糙，柠檬黄色，难剥离，富含柠檬香气的油点，瓢囊8-11瓣，汁胞淡黄色，果汁酸至甚酸，种子小，卵形，端尖；种皮平滑，子叶乳白色，通常单或兼有多胚。花期4-5月，果期9-11月。
染色体数X＝9，2n=18, 36。
产长江以南。
柠檬是从国外引进，栽培史短，较常见的有：Eureka（尤力克），又称油力克、油利加，果顶有明显的乳头状凸尖，果皮较粗糙，间有纵棱，皮厚，果肉甚酸。Lisbon（里斯本），果顶有较长的乳头状凸尖且常稍向一侧弯斜，果皮较光滑，果基也有较明显的颈部，果肉酸味甚浓。Meyer（北京柠檬），又称香柠檬、美华柠檬，是在北京丰台选育的品种，抗寒性强，果皮薄而甚光滑，果顶有短凸尖，果肉香气浓，但含酸份较低。尚有称为粗柠檬 C. jambhiri Lush. 的，它原产印度，广东和四川个别柑橘场有引栽。Swingle学派认为它是柠檬与宽皮橘类的杂交种，它的果皮柠檬黄色，甚粗糙，果顶有短的肉瘤状突起，果心大而空，种子少。生长快，抗旱，抗线虫为害。国外用作砧木材料。
柠檬果皮含黄酮类化合物：rutin、diosmin 等，前者即芦丁，后者即柠檬素，或所谓维生素“P”。柠檬花、叶及果皮都含柠檬精油，是烯萜类的种种氧化衍生物，如醇、醛、酮、酯等类，其中以果皮含的右旋柠檬烯d-limonine最多，占油量中的90%，其次为methyl heptanone、terpineol及凝固性的柠檬油素等。种子又含limonin。

《云南植物志》|| 芸香科 Rutaceae nom. conserv. ||柑桔属 Citrus L. ||柠檬 Citrus limon (L.) Burm. f.

7.柠檬（通称）
麻老果（傣语）
Citrus limon (L.) Burm. f. (1768); J. C. Th. Uphof (1959); Murata (1973); J. R. Press, in Hara (1979); "图鉴" 补编 (1983), in clavi; C. Y. Wu et al. (1984).
Citrus medica var. 2 limon L. (1753); C. medica var. limonum Hook. f. (1875); C. limonu Risso (1813); C. communis Poiteau (1846); C. medica f. limon (L.) Hiroe (1974).
小乔木，高3—5米，具直刺。叶互生，淡绿色，椭圆状卵形，长6.5—10厘米，宽3—4.5厘米，顶端短渐尖或钝，叶缘具细齿，具叶柄，柄上有狭翅，叶柄顶端有关节。花单生或簇生于叶腋内，花瓣4—5，匙形，长1.3—1.7厘米，宽4—6毫米，外面淡红色，内面白色；雄蕊约20枚，子房圆锥状。果椭圆形至卵形，顶端乳头状，长7.5—12.5厘米，粗4—6厘米，果皮亮黄色，表皮粗糙，囊瓣8—10，果肉味极酸，每瓣内有种子3—4粒，卵圆形，淡黄色。花期春季，果期秋季。
原产亚洲；中部及西双版纳栽培；长江以南常见栽培。
本种与黎檬（Citrus limonia Osb.）十分近似，其区别点为1. 花瓣冠幅3.5—4.5厘米；2. 叶大，卵状椭圆形；3. 果皮厚，油胞小并下凹，表皮粗糙；4. 种子的胚为白色。
现已广泛栽培于南欧、意大利、加里佛里亚，佛罗里达等地。品种很多。用果皮蒸馏可以得到昂贵的柠檬油（oil of Lemon，Cedro oil）这种精油用途极广，可用于驱风、香水、食品工业。
我国传统用药经验用鲜品花治乳腺炎，作药引。

《Flora of China》|| Rutaceae || Citrus ||柠檬 Citrus ×limon

9. Citrus ×limon (Linnaeus) Osbeck, Reis Ostindien China. 250. 1765.

柠檬 ning meng

Citrus medica Linnaeus var. limon Linnaeus, Sp. Pl. 2: 782. 1753; C. ×aurantium Linnaeus subsp. bergamia (Risso) Engler; C. ×aurantium var. bergamia (Risso) Brandis; C. ×aurantium var. mellarosa (Risso) Engler; C. ×bergamia Risso; C. ×bergamia subsp. mellarosa (Risso) Rivera et al.; C. ×bergamota Rafinesque; C. ×limodulcis Rivera et al.; C. ×limonum Risso; C. medica Linnaeus f. limon (Linnaeus) Hiroe; C. medica subsp. limonum (Risso) J. D. Hooker; C. medica var. limonum (Risso) Brandis; C. ×mellarosa Risso; C. ×meyeri Yu. Tanaka; Limon ×vulgaris Ferrarius ex Miller (1754), not C. ×vulgaris Risso (1813).

Small trees. Branches ± spiny. Young leaves and flower buds reddish purple. Leaf blade ovate to elliptic, 8-14 × 4-6 cm, margin conspicuously crenulate, apex usually mucronate. Flowers solitary or several in fascicles. Flowers bisexual or male by ± complete abortion of pistil. Calyx cup-shaped; lobes 4 or 5. Petals 1.5-2 cm, outside purplish, inside white. Stamens 20-25 or more. Ovary subcylindric or barrel-shaped; stigma clavate. Fruit yellow, ellipsoid to ovoid, narrowed at both ends, surface usually coarse and lemon scented, apex usually with a mammilla; pericarp thick, difficult to remove; sarcocarp in 8-11 segments, pale yellow, acidic. Seeds ovoid, small, apex acute; seed coat smooth; embryo usually solitary but sometimes numerous; cotyledons milky white. Fl. Apr-May, fr. Sep-Nov. 2n = 18, 36.

Cultivated and sometimes naturalized in S China.

The parents of the lemon are Citrus ×aurantium and C. medica. Backcrosses with either parent give a range of sour to sweet lemons which go under various names and perhaps would best be considered as forming cultivar groups, e.g., Bergamot Group. The rough lemon, C. ×taitensis Risso (C. ×aurantium subsp. jambhiri Engler; C. ×jambhiri Lushington; C. ×sinensis subsp. jambhiri (Lushington) Engler), sometimes included here, is perhaps C. medica × C. reticulata.

The name "Citrus limonia" has been misapplied to other Citrus taxa.