An enigmatic genus on an enigmatic island: the re‐discovery of Kalappia on Sulawesi

The Indonesian island of Sulawesi possesses a biota defined by anomaly (Wallace 1869). It has high levels of endemism (Michaux 2010) but, despite attracting research interest since the time of biogeographic pioneers such as Alfred Russell Wallace, the island remains relatively undocumented (van Welzen et al. 2011) with collection rates below much of the wider region (Kessler et al. 2002). As currently known, the flora suggests a placement within the Austral‐Asian amalgamative region of Wallacea, which encompasses the chain of islands between Borneo and New Guinea (van Welzen et al. 2011). The region has been designated a biodiversity hotspot. Sulawesi, the largest landmass within Wallacea, is absolutely critical to successful conservation of its diverse fauna and flora (Cannon et al. 2007). Extraction of both natural gas and valuable metal ore deposits is a major contributor to deforestation in Sulawesi, particularly the mining of nickel, across the 15,400‐km2 ultramafic outcrop that constitutes approximately 8.8% of the total land area (van der Ent et al. 2013). Extraction is most prominent in the Soroako area close to the town of Malili (Fig. 1). A number of botanists including Meijer, Reppie, and van Balgooy visited Malili from the 1930s to the 1970s. Among the collections made were fewer than 10 specimens of a legume tree species from a very small area of wet tropical forest. This was described as Kalappia celebica, the single species in the genus (Kostermans 1952). The taxon exhibits anthers that dehisce via a pair of apical pores. This type of anther dehiscence is rare in legumes but observed in other closely related taxa and is indicative of buzz pollination by bees (Tucker 1998). The anthers of Kalappia also feature a prominent spur that extends from the base of one of the two apical pores (Fig. 2). This combination of characters is apparently unique to Kalappia. The function of these spurs may be homologous with the porate anther appendages found in the Melastomataceae that are thought to enhance visual attractiveness and facilitate gripping for visiting bees (Renner 1989). Timber of Kalappia trees has been exploited for use in house construction, ship‐building, and in furniture manufacture. Even prior to scientific description of the species, timber export to Makassar, the largest city in Sulawesi, had been observed by Kostermans (1952). This evident threat to the species coupled with its restricted distribution led to an IUCN red list conservation assessment of “Vulnerable” (IUCN 1998). A lack of collections since the 1970s gave rise to the