After the publication of the Citrus Genera of Linnaeus in 1753, the need for a more comprehensive treatment of the genus Citrus and of the closely allied genera became apparent. The first attempt to combine all the species of Citrus and of the allied genera into a comprehensive genus was made by John Ray in 1785. The result was a key to the tree and shrub genera of the British Isles, now lost, but included in his Catalogus sive descriptio plantarum ingentium (1787, 2 vols.). This key was expanded in 1796 by G. B. de Candolle and later published as part of his Prodromus Systematis Naturalis Regni Vegetabilis (1824, 5 vols.). The most complete treatment of the Aurantioideae was published in 1884 by George Bentham and the most complete treatment of the Citricoideae by Collins in 1896. A detailed study of the Citricoideae was published by Johnson in 1926. In the following pages, the botanical relationships of the three tribes and subtribes of the Aurantioideae are discussed. The forty-three genera of the subtribe Clauseneae, the eighteen genera of the tribe Citreae, and the four genera of the subtribe Balsamocitrinae are treated in a systematic order. Finally the four genera of the subtribe Cymbeliinae are discussed.
THE CLASSEANAE, A ROSTRATIFORM TRIBE OF THE AURANTIOIDEAE The Classtiae are defined in the Rutaceae by having the calyx of the flower with two lobes, the corolla usually having two lobes, and the fruit with two locules. The subtribe contains Clausena, Microcitrus, and Myristica. The species of Clausena 827ec27edc