Agathis is one of two genera of a taxonomically isolated southern hemisphere conifer family, Araucariaceae. The geographical range and ecological niches of the thirteen species are briefly described. On the Gondwanic fragments of north Queensland and New Caledonia there are respectively three and five sympatric species mostly with a different habitat. Elsewhere, from New Zealand and Fiji west throughout the Malay archipelago to Sumatra, the species are (with one minor exception) allopatric and all show ecotypic differentiation. In Malesia Agathis only dominates and regenerates in situ in forests on poor sites but in Melanesia it is not restricted in this way. The hypothesis is put forward that Agathis has expanded its range from these two Gondwanic centres and is most successful in competition with angiosperms in relatively species-poor forests.
PAGE, C.N. AND WHITMORE, T.C. (1980). Evolutionary implications of the distribution and ecology of the tropical conifer Agathis. New Phytologist. 84 (2) pp. 407-416 [DOI: 10.1111/j.1469-8137.1980.tb04440.x]