In the last decade a lot of work has been devoted to the genera of Araceae. The number of new genera erected since Mayo et al. (1997) mentioned 105 published genera has risen to 118 published genera and approximately 3500 published species (Boyce & Croat 2011, Boyce & Wong 2012, Nauheimer & Boyce 2013). This number of genera is likely to grow further and it has been predicted that it will reach 132 genera with an expected total species number of about 6000 (Boyce & Croat 2011).
Of the estimated 42 genera in the Malesian region, the Indonesian Archipelago is considered to be the richest in plant diversity, with 35 published genera, or 29.7% of the total genera of Araceae in the world (Fig. 4). This number is expected to rise to 39 genera (Table 1). The main islands of the Indonesian archipelago are grouped into distinct regions based on their flora i.e. the flora of Java shows affinities with that of Sumatera and the Malay Peninsula; the flora of Sulawesi has a strong similarity with the Philippines; the Kalimantan flora is more similar to that of Malaysian Borneo and Brunei; and the flora of the Indonesian half of the island of New Guinea is closer to that of Papua New Guinea than the rest of Indonesia (Yuzammi 2000). This is due to the rifting of continental fragments of Laurasia and Gondwanaland during the Cretaceous period and their collision during the Tertiary period in central Malesia (Whitmore 1987). There is a significant difference between the floras of Java and New Guinea, reflecting the discontinuity between the Sunda Shelf and the Sahul region, and coinciding with Wallace’s line, which separates West from East Malesia.
The number of published genera of Araceae currently found in Indonesia, and the additional genera that may be expected to be located within the Indonesian archipelago following further exploration and taxonomic review
The number of published genera in Indonesia
Expected to occur in Indonesia