Tree Flora of Sabah and Sarawak, Volume I - ITTO

TREE FLORA OF SABAH AND SARAWAK VOL. 1 (1995)
on a smaller scale presumably owing to its youth, a regionally widespread upper montane
and alpine element. The extensive ultramafic extrusions support a number of endemics,
both in the lowlands and also on Kinabalu to which such notable species as Scaevola
micrantha, S. chanii and Piltosporum linearifolium are confined. But the Province is
notable in addition for its lowland endemic flora, which includes the dipterocarps
Dryobalanops keithii, Hopea badiifolia, Parashorea tomentella, Shorea symingtonii, S.
waltonii, all of S. parvifolia type MDF, and, in this volume, Dacryodes elmeri, Kokoona
sabahana, Microtropis sabahensis, Parinari argento-sericea, Connarus agamae, Atuna
cordata, Sarcotheca rubrinervis, Maclurodendron pubescens, Melicope jugosa, M sororioa,
M subunifoliolata, Monanthocitrus oblanceolata, and Turpinia nitida. Also, a number of
Philippine species including Dipterocarpus validus, Protium connarifolium, Pitlosporum
resiniferum, Melicope bonwickii, M denhamii, Turpinia borneensis and Scaevola
micrantha, and species such as Canarium asperum, C. decumanum and Kibara obtusa are
only known from this part of Borneo. Several of these are confined to ultramafic
substrates.
The southward extent of this Province into East Kalimantan is as yet inadequately
understood. There is limited ultramafic rock in Kalimantan but some species of the zonal
clay soils, such as D. keithii, hardly reach Tidung while others, such as H. badiifolia,
extend as far as Balikpapan. This variable extent of ranges is not surprising in the Shorea
parvifolia type MDF on clay soils, which extends continuously over the hills of East and
Central Borneo. A number of other Philippine species such, for instance, as the
dipterocarps Parashorea malaanonan, Shorea almon and S. falciferoides, also extend
westward into north and central Sarawak.
Lastly, there is an element in the Shorea parvifolia type MDF, represented by such species
as Dipterocarpus mundus, D. pachyphyllus, Hopea bullatifolia, H centipeda, H dasyrrhachis,
H jluvialis, H megacarpa, Shorea agamii ssp. diminuta, S. asahi, S. collaris, S. iliasii, Vatica
endertii and V granulata, which have been found from innermost lowland Sarawak across to
the DIu Barito, and which may eventually delineate a distinct central Bornean transmontane
floristic province.
References
Anderson, J.A.R. 1963. The flora of the peat swamp forests of Sarawak and Brunei
including a catalogue of all recorded species of flowering plants, ferns, and fern allies.
Gard. Bull. Sing. 20: 131-228.
Ashton, P.S. 1964. Ecological Studies in the Mixed Dipterocarp Forests of Brunei State.
Oxford Forestry Memoirs 25.
Ashton, P.S. 1972. The quarternary geomorphological history of western Malesia and
lowland forest phytogeography. In P. & M. Ashton (eds.), Hull Geog. Dept. Misc. Series
13. Transactions of the second Aberdeen-Hull symposium on Malesian ecology: The
quarternary era in Malesia. Pp. 35-49
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