A synopsis of the endemic plant genera of Borneo

Abstract

The large, tropical island of Borneo has some of the world's richest habitats for plant life, but faces increasing pressures from anthropogenic activities that threaten its biodiversity. With a good portion of the Bornean flora not critically studied, a comprehensive documentation of the numerous endemic taxa expected for the island is not yet complete. It is not known what the relative significance of endemic genera is compared to Bornean centres of endemism documented or predicted through modelling, and if they can inform current conservation plans. As a first step, we here present a synopsis of the endemic genera of Borneo, based on a comprehensive study of literature, herbarium specimens and distributional data, and an investigation of whether the genera have been included in molecular phylogenetic studies that confirm their monophyly. Such a review is timely since many generic delimitations have been shaped by molecular evidence used to test morphology‐based taxonomy, while botanical collection and revisionary efforts continue. Our findings suggest that 65 vascular plant genera from 25 families may be considered endemic to Borneo. More than two‐thirds (48) of these genera have had at least one species included in molecular phylogenetic studies, but of these, only 39 have been sufficiently sampled to be considered monophyletic with high confidence, or they are monotypic. Slightly over half (38) of the endemic genera are herbaceous. A majority of the genera have fruits or seeds specialised for dispersal by abiotic vectors, or unspecialised seeds. Almost two‐thirds (42) of the endemic genera are monotypic, and some of these could represent relict lineages. We expect the current list of endemic genera to be relatively stable and aligned with recent taxonomic concepts, and that it serves to illuminate an interesting aspect of Borneo's unique assemblage of endemic species.

Checklist of aroids (Alismatales, Araceae) from Sabah (Malaysian Borneo)

“…Apart from Tawaia, the only endemic aroid genus, Sabah also harbours a few more endemic genera in Orchidaceae (monotypic Jejewoodia Szlach. and Kipandiorchis P.O'Byrne & Gokusing), Euphorbiaceae (Borneodendron Airy Shaw), Loranthaceae (Lampas Danser), and Rubiaceae (Phyllocrater Wernham) (Neo et al 2020).…”

The The ginger genus Burbidgea confirmed in the flora of the Philippines

“…Type: Burbidgea nitida Hook.f. A genus of herbaceous perennials, terrestrial or epiphytic plants currently represented by six species which are native to Borneo (Smith 1972;Neo et al 2020;Newman & al. 2005-).…”

Plant diversity in logged over forest in Mahakam Ulu, East Kalimantan, Indonesia

“…Forty species of Pinanga grow in Borneo (Govaerts et al 2018). Borneo is home to 65 vascular plants genera from 25 families considered endemic to Borneo (Neo et al 2020). Mlaha's findings reinforce that Borneo is unique as a biodiversity hotspot.…”

“…Mlaha's findings reinforce that Borneo is unique as a biodiversity hotspot. Mlaha or Buan tree in local name (E. spectabilis) is special because it is monotypic, meaning there is only single species in the genus, and thus far the only known genera and species of the endemic tree of Borneo grows in two areas, East Borneo and South Borneo (Neo et al 2020).…”