A Remarkable New Species of <I>Jarandersonia</I> (Malvaceae-Brownlowioideae) from Central Kalimantan, Borneo

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. Keywords—Borneo, endemic, flora, Jarandersonia, Malvaceae-Brownlowioideae, taxonomy. Jarandersonia Kosterm. (Malvaceae-Brownlowioideae) was established as a monotypic genus by Kostermans (1960) based on Jarandersonia paludosa Kosterm. (currently a synonym of Jarandersonia purseglovei (Kosterm.) Kosterm.), an endemic species that occurs in Sarawak, Borneo. Kostermans (1960, 1970) recognized the genus based on the distinctness of its fruit covered with slender spines bearing setose hairs. It com- prises five species distributed in Borneo (Kostermans 1970). Jarandersonia purseglovei and J. spinulosa Kosterm. are endemic to Sarawak, J. rinoreoides Kosterm. is endemic to Sabah, while the other two species J. clemensiae (Burret) Kosterm. is known from Sarawak and Kalimantan, and J. parvifolia Kosterm. occurs in Sarawak, Brunei and Kalimantan. Recent phylogenetic analy- sis of plastid atpB, rbcL and ndhF DNA sequences support the placement of Jarandersonia, together with Brownlowia Roxb., Diplodiscus Turcz. and Pentace Hassk. in the Brownlowioideae clade of Malvaceae s. l. (Judd and Manchester 1997; Alverson et al. 1999; Bayer et al. 1999; Nyffeler and Baum 2000). The author's recent revision of the genus for the Tree Flora of Sabah and Sarawak Project recognized six species of Jarandersonia from Borneo. Of these, J. pentaceoides, endemic to central Kalimantan, is new to science and is here described for the first time as a precursory paper to the publication of the revi- sion for the genus.