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Family: Rutaceae

Kingdom: Plantae Rank: Family Parent: Sapindales Status: Valid

Common Names:

  • CITRUS - English, United States of America
  • RUE FAMILY - English, United States of America

Morphological Description

Family Recognition in the Field: Usually shrubs or trees (1 can be herbaceous) with alternate, scented, gland-dotted leaves (glands easily seen when the leaves are held up to a strong light ).

Diagnosis: Perennial herbs, shrubs, or small trees; leaves alternate, simple or compound; leaf blades entire or toothed, usually firm, thickish, aromatic, with oil dots (glands) usually visible when backlit; flowers terminal or lateral, perfect or unisexual, solitary or in racemes, cymes, or short broad panicles; sepals 3-5; petals 3-5; stamens 3-20; pistils 1-3, ovary superior, raised on a disk-like projection of the receptacle; fruits various.


Notes: A medium-large (1,800 species in 156 genera), cosmopolitan, but especially tropical and warm temperate family of mainly trees and shrubs or rarely herbs including the economically important citrus fruits (genus Citrus native to se Asia and Malay Peninsula); they are sometimes thorny and often have bitter terpenoids or alkaloids; the tissues are usually aromatic due to the presence of essential oils. Some species are cultivated for their essential oils (e.g., Ruta for oil of RUE) or as ornamentals. Old World Dictamus albus L. (GASPLANT, BURNINGBUSH) has so many glands releasing volatile, inflammable oil vapors that in hot still weather the vapors can be ignited with a flash. Citrus fruits, including GRAPEFRUIT, LEMON, LIME, and ORANGE, are a type of specialized berry known as a hesperidium; the individual segments that we eat represent single carpels. The TEXAS RED GRAPEFRUIT, Citrus x paradisi (L.) Macfad. [C. maxima x C. sinensis] (cultivar "Ruby" (redblush)), was designated the state fruit of Texas in 1993; while this cultivar was developed in TX, the parents are introduced (Jones et al. 1997). [a PLANT OF TOXIC/ POISONOUS NATURE]. Citrus species contain furocoumarins that can photosensitize the skin making it much more sensitive to sun- light; the result is that sun exposure can sometimes result in reddening, swelling, and blistering (Fuller & McClintock 1986; D.M. Eggers-Ware, pers. comm.); after handling citrus fruits, the hands should be washed before extensive sun exposure; other Rutaceae (e.g., Ptelea , Thamnosma) are also capable of causing such phytophotodermatitis (Lampe 1986; L. Woodruff, pers. comm.). According to Lampe (1986), "... the affected skin becomes pigmented and may remain so for many months. Sometimes precise leaf patterns can be seen as dark tattoos on the skin." Family name from Ruta, RUE, a genus of 7 species native from Macaronesia and the Mediterranean to sw Asia; it has been cultivated since ancient times for its strong flavor and for medicinal uses (due to the presence of ethereal oils); [a PLANT OF TOXIC/ POISONOUS NATURE]. however, it can cause dermatitis in some individuals. (Latin: ruta, rue, a bitter herb, bitterness, unpleasantness, in reference to the bitter taste) (subclass Rosidae).