A taxonomic revision of the myrmecophilous species of the rattan genus Korthalsia (Arecaceae)

The rattan genus Korthalsia Blume (Arecaceae: Calamoideae: Calameae) is widespread in the Malesian region. Among the 28 accepted species are 10 species that form intimate associations with ants. The ants inhabit the conspicuous ocreas that are produced by these species, using them as domatia to care for their young and aphids. As a foundation for future work, we present here a taxonomic treatment of the myrmecophilous Korthalsia species, based on extensive research pursued both in the herbarium and the field. In addition, we conduct detailed morphological characterisation of the structure and development of ocrea using light and scanning electron microscopy. Descriptions, illustrations, keys and distribution maps are presented for all 10 species, along with microscopic images of ocrea morphology and development for selected species.