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Coconut is the only species in the genus Cocos in the family Arecaceae. All forms known to date are diploid (2n = 32). No closely related species with even partial inter-fertility has been reported (Bourdeix et al., 2001). Vernacular names and descriptions used in 17th century still survive today, and the first systematic classifications of populations (hereafter referred to as varieties) identified two subtypes, Tall and Dwarf, and were named as C. typica and C. nana. The more recent naming system adopted by the International Coconut Genetic Resources Network (COGENT) combines a country location with palm stature, such as Malayan Dwarf (MD) and Panama Tall (PT), or may indicate hybrid parentage, such as Maypan (MD×PT), or include fruit colour or other plant traits, e.g. spicata, the non-branched inflorescence form, or makapuno or kopyor with a unique soft kernel type.

The classification recognizes that the Tall form is predominantly cross-pollinated while the Dwarf form is highly self-pollinated. Self-pollination in the Dwarf has likely resulted from modifications that have taken place in the structure of the flower during the dwarfism evolutionary process which subsequently have been amplified through selection under cultivation. However, when hand pollinated, Dwarf types remain readily fertilized by the Tall. The less vigorous Dwarf survives as a group because its recessive fruit colour markers, especially orange and yellow, can be recognized and selected. The Dwarf form was preserved by selection for its early fruiting, ease of harvest and attractive fruit colour.

By considering the proportion of each fruit component, i.e. husk, shell, water and kernel, at a definable stage of fruit development, researchers can differentiate between coconut populations even in the field. In addition, it is now possible to undertake the same kind of differentiation by DNA profiling, which has become routine through the use of a microsatellite kit.