Included here is Sulawesi (formerly Celebes) and its neighbouring islands.

Sulawesian Peatswamp Forest

The only major area of peatswamp on Sulawesi is the Aopa Swamp 100 km west of Kenderi. In the undisturbed areas these rich forests reaching heights of up to 35 m. Strangling figs are common, while other trees include Artocarpus teysmannii, Baeckia frutescens, Calophyllum soulattri, Diospyros malabarica, Geunsia paloensis, Hopea gregaria, Premna foetida and Saccopetalum horsfieldii. There are also many palms including species of Arenga and Livistona and climbers are common. Epiphytes, on the other hand, are comparatively rare, but the undergrowth includes a varied assemblage of herbaceous species.

Sulawesian Swamp Forest

Fresh water swamps more or less devoid of peat and are mainly found on riverine alluvium or alluvium deposited by lakes such as Lake Lindo and Lake Poso. The tree species composition of these forest can vary considerable but may include Barringtonia racemosa, Elaeocarpus littoralis, Polyalthia lateriflora, Quassia indica and Terminalia copelandii, while in the swamps of Lake Ranu species like Calophyllum soulattri, Mimusops elengi and the endemic Haplolobus celebicus (Burseraceae) have been recorded. Other endemic species include trees such as Guioa hirsuta (Sapindaceae) and Terminalia kjellbergia (Combretaceae) and shrubs such as Diplycosia minutiflora (Ericaceae). A feature of these forests is the presence of large numbers of pitcher plant (Nepenthes) which are generally climbing of scrambling plants

Sulawesian Eucalyptus Riverine Forest

These forests, which are confined to the margins of rivers, are dominated by the distinctive Eucalytpus deglupta, which can reach heights of up to 60 m. It is also the only species of this huge genus (about 500 species) that is regularly found in rainforest.  Other large trees include Duabanga moluccana, Dracontomelon dae, Emirilla ovalis, Octomelus sumatrana and Pometia pinnata. These riverine forests are subject to regular flooding and the deposition of new sediments, and an interesting adaptation of a number of trees, such as Sauravia oligolepis, is to produce inflorescences at the base of their trunks, which eventually push their fruit into the soil. This is phenomenon known as geocarpy and helps to prevent their seeds being swept away by river foods.

References

Leith, H. & Werger, M. J. A. 1989. Ecosystems of the World 14B - Tropical Rain Forests. Elsevier Scientific Publishing Company.

Meijer, W. 1976. Botanical Explorations in Celebes and Bali. National Geographic Society Research Reports, 60: 583-605.

Steenis, C. G. G. J. van. 1957. Outline of the vegetation types in Indonesia and some adjacent regions. Proceedings of the Pacific Scientific Congress, 8: 61-97.

Whitmore, T. C. & Sidiyasa, K. 1986. Composition and structure of a lowland rain forest at Toraut, northern Sulawesi. Kew Bulletin, 41: 747-756.

Whitten, A. J., Mustafa, M. & Henderson, G. S. 1987. The Ecology of Sulawesi. Gadjah Mada University Press.