Abstract— A new species, Jarandersonia pentaceoides (Malvaceae-Brownlowioideae), endemic to central Kalimantan, Borneo is described and illustrated. Salient morphological features of the new species that can be used to distinguish it from previously known
species of the genus (i.e. J. clemensiae, J. parvifolia, J. purseglovei, J. rinoreoides and J. spinulosa) are tabulated. These include: the densely stellate-lepidote and dentate-lepidote edges of tertiary veins and honeycomb-like quaternary veins on the lower
leaf surface, the kneed petiole that is swollen at both ends, and the sparsely stellate-lepidote and tufted-hairy seed coat. A key to the species of Jarandersonia is provided, as is a map of its distribution.