There are about 250 species of Cinnamomum in the tropical and subtropical regions, mostly in Asia and some in South and Central America, and Australia (Mabberley 2008). To date, 628 binomials of the genus have been published on the International Plant Names Index (http://www.ipni.org, last accessed 30 October 2010) and 33 of these are attributed to species occurring in Borneo. Kostermans was the pioneering figure in the revision of Malesian Lauraceae in the 20th century. His work, although not complete, has been ground-breaking and has set the momentum towards the family revision in Malesia. He had published many precursory papers on Malesian Lauraceae, some of which are relevant to Cinnamomum (Kostermans 1952, 1957, 1964, 1969, 1970, 1986, 1988). His last major revision of Cinnamomum was published in Gingkoana in 1986, focussing on species from the eastern Malesian region to Australia (Sulawesi, the Philippines, Moluccas, New Guinea, Solomon Islands, Pacific Area and Australia). Other revisional studies of Bornean Cinnamomum have generally been subsets of geographically broader revisional work in the Malesian region (Blume 1851; Miquel 1858, 1864; Cammerloher 1925).
Cinnamomum is usually readily recognised by trinerved and fragrant leaves, paniculate inflorescences, flower with nine stamens and fruits seated on a cupule. At suprageneric level based on chloroplast and nuclear DNA studies, Cinnamomum is placed together with other Neotropical genera (Aiouea pro parte, Mocinnodaphne, and Ocotea pro parte) in a clade within Cinnamomeae (Chanderbali et al. 2001). Asian Cinnamomum was shown to be monophyletic and sister to the New World species (Chanderbali et al. 2001). At the infrageneric level, there is no comprehensive molecular study, and nucleotide sequences are available for only a few wild and frequently cultivated species. Meissner (1864) recognised two sections, namely section Malabathrum characterized by opposite or subopposite leaves, trinerved or triplinerved leaf venation and non-perulate buds and the other section is Camphora which is mostly with alternate leaf arrangement, pinnate leaf venation and perulate buds. The section Camphora is mostly restricted to the Northern Hemisphere. This division has been accepted by some authors who have worked in the Malesian Lauraceae (Gamble 1912; Ridley 1924; Kostermans 1986).