Citrus

Round kumquat Citrus japonica, copyright Phuong Tran.

Belongs within: Citroideae.

Citrus is a genus of shrubs and small trees, many species of which are widely grown for their edible fruits. The taxonomy of this genus is particularly complex, with most cultivated taxa being of hybrid origin.

See also: Are you sucking on a lemon or a lime?

Characters (from Flora of China): Shrubs or small trees, evergreen, rarely deciduous. Young branches often flat and angled, usually with solitary (rarely paired) spines at axils. Leaves 1-foliolate, rarely 3-foliolate or simple; petiole usually articulated with base of leaf blade, usually conspicuously winged; leaf blade subleathery to leathery, with dense pellucid fragrant oil dots, margin crenulate or rarely entire. Flowers axillary, hermaphrodite or male, solitary or in small fascicles, fragrant. Calyx cup-shaped; lobes 3-5, subglabrous. Petals (3 or)4 or 5(-8), white or outside pinkish red, imbricate, thick. Stamens usually 4(-10) × as many as petals, free or basally coherent. Disk annular or short, with nectary glands. Ovary (3-)5-14(-18)-loculed, each locule with 2-8 or more ovules; stigma large. Fruit a berry (hesperidium) with sarcocarp segments of pulp vesicles and adaxially attached seeds. Seed coat smooth or ridged; embryo(s) 1 to many, like cotyledons milky white, green, or rarely yellowish, germination hypogeous.

<==Citrus
    |--C. aurantifolia CR01
    |--C. aurantium A-G91 [incl. C. vulgaris C55]
    |--C. bergamia R-CT01
    |--C. decumana C55
    |--C. deliciosa R-CT01
    |--C. glauca MS06
    |--C. grandis A-G91
    |--C. japonica MS06
    |--C. javanica C55
    |--C. junos LO98
    |--C. latifolia CR01
    |--C. limetta A-G91
    |--C. limon A-G91
    |--C. medica A-G91
    |--C. nobilis C55
    |--C. paradisi A-G91
    |--C. reshni CR01
    |--C. reticulata A-G91
    |--C. sinensis R-CT01
    `--C. tachibana MH98

*Type species of generic name indicated

REFERENCES

[A-G91] Al-Gboory, J. I. 1991. Biology of oriental citrus mite, Eutetranychus orientalis (Klein) on different citrus species. In: Dusbábek, F., & V. Bukva (eds) Modern Acarology: Proceedings of the VIII International Congress of Acarology, held in České Budĕjovice, Czechoslovakia, 6–11 August 1990 vol. 2 pp. 607–611. SPB Academic Publishing: The Hague.

[C55] Candolle, A. de. 1855. Géographie Botanique Raisonée: Ou exposition des faits principaux et des lois concernant la distribution géographique des plantes de l’époque actuelle vol. 2. Librairie de Victor Masson: Paris.

[CR01] Chagas, C. M., V. Rossetti, A. Colariccio, O. Lovisolo, E. W. Kitajima & C. C. Childers. 2001. Brevipalpus mites (Acari: Tenuipalpidae) as vectors of plant viruses. In: Halliday, R. B., D. E. Walter, H. C. Proctor, R. A. Norton & M. J. Colloff (eds) Acarology: Proceedings of the 10^th International Congress pp. 369–375. CSIRO Publishing: Melbourne.

[LO98] Lack, H. W., & H. Ohba. 1998. Die Xylothek des Chikusai Kato. Willdenowia 28: 263–276.

[MH98] Morikawa, H., A. Higaki, M. Nohno, M. Takahashi, M. Kamada, M. Nakata, G. Toyohara, Y. Okamura, K. Matsui, S. Kitani, K. Fujita, K. Irifune & N. Goshima. 1998. More than a 600-fold variation in nitrogen dioxide assimilation among 217 plant taxa. Plant, Cell and Environment 21: 180–190.

[MS06] Muellner, A. N., V. Savolainen, R. Samuel & M. W. Chase. 2006. The mahogany family "out-of-Africa": divergence time estimation, global biogeographic patterns inferred from plastid rbcL DNA sequences, extant, and fossil distribution of diversity. Molecular Phylogenetics and Evolution 40 (1): 236–250.

[R-CT01] Ragusa-di Chiara, S., & H. Tsolakis. 2001. Phytoseiid faunas of natural and agricultural ecosystems in Sicily. In: Halliday, R. B., D. E. Walter, H. C. Proctor, R. A. Norton & M. J. Colloff (eds) Acarology: Proceedings of the 10^th International Congress pp. 522–529. CSIRO Publishing: Melbourne.