Over 500 species have been published in the pan-tropical genus Elatostema Forst. (Urticaceae). This paper focuses on phylogenetic relationships within small clades of closely related species of Elatostema, particularly high elevation endemic species on Mount Kinabalu on the island of Borneo and species in neighboring mountain floras. Species distributions have been mapped in detail for Mount Kinabalu and it is therefore possible to relate the phylogeny to spatial data contained in the Kinabalu GIS (Geographical Information System), such as elevation, slope, aspect and insolation as well as geological and ecological data extracted from a Landsat TM image. Mount Kinabalu is a granitic pluton of recent geological origin, and many of its plant communities sort out not just by elevation, but also due to ultramafic outcrops occurring at various elevations. Understanding the relationship between phylogeny, geomorphology, and endemism is not just desirable for Elatostema. Ultramafic outcrops on Kinabalu have high levels of endemicity in many taxonomic groups.

Key words: Elatostema, endemism, GIS, Kinabalu, phylogeny, ultramafic, Urticaceae