The botanical hierachy of the Genus Camellia has developed considerably as the number of species nominated by botanists, increased from the original two, C. japonica and C. sinensis, listed by Linnaeus (1735) as the genera Camellia and Thea, up to the present day 267 including varieties of species.
J. Robert Sealy's monograph, A Revision of the Genus Camellia, published by the RHS in London in 1958, codified and stabilized the botanical nomenclature relating to the camellia species recognised at that time. He divided the Genus into 12 sections and described 87 species.
As, in the intervening years since 1958, many more species had been nominated and described by botanists, Chang Hungta of the Sunyatsensi Unversity, Nanjing, China, carried out a further investigation, leading to a reclassification of Sealy's hierachy to suitably include the added number. He published his monograph on the Genus Camellia in 1981. This was updated and translated into English with the assistance of Dr Bruce Bartholomew, of California, USA, and published by Timber Press, Portland, Orgon in 1984. This includes 201 species or otherwise differentiated groups of camellias. Chang divided the Genus into 4 Subgenus with a total of 20 sections. Since that time a further 66 species and varieties have been added by botanists, making a total of 267 by 1991.
Chang accepted most of Sealy's work and did not fully re-describe the species dealt with by him, so that the two monographs together are neccesary to study the main body of the species material.
The Chang hierachy is as follows: