Plant Formations in the Malayan BioProvince Peter Martin Rhind Malayan Mixed Lowland Dipterocarp Forest These forests occur from sea level to an altitude of about 750 m. In Endau-Rompin they can be broadly divided into two types. One is characterized by Dipterocarpus and Shorea, and mainly occurs at altitudes below 250 m, and is common, for example, in the valleys of the Endau River and its tributaries. The other is characterized by Dryobalanus aromatica, which occurs normally at altitudes below 300 m; it is common, for example, in the northeast and eastern areas of the Kinchin and Lamakoh valleys. Both these forests contain massive trees with canopies up to 30 m high and emergents reaching 45-50 m, and have many common trees. The main dipterocarps are Dipterocarpus baudi, D. concavus, D. costulatus, D. crinitus, D. gracilis, D. kerrii, Shorea acuminata, S. blumutensis, S. maxwelliana, S. ovalis, S. paevifolia, S. pauciflora, S. singkawang and the endemic S. bentongensis (Dipterocarpaceae). Dryobalanops aromatica is distributed gregareously in various river valleys while the endemic Hopea johorensis (Dipterocarpaceae), has a more patchy distribution but is often found in treefall gaps. Other large trees include Artocarpus lanceifolius, Coelostegia borneensis, Dialium platysepalum, Dillenia excelsa, Dyera costulata, Endospermum malaccensis, Koompassia malaccensis, Parkia speciosa, Pouteria malaccensis, Scaphium macropodum, Swintonia floribunda var. penangiana and the endemic Sarcotheca laxa var. sericea (Oxalidaceae). Second tier species include Agostistachys borneensis, Aporusa microstachya, Elateriospermum tapos, Pimelodendron griffithianum, Horsfieldia superba, Knema furfuracea, Myristica iners, Xerospermum noronhianum and the endemic Dillenia albiflos (Dilleniaceae) and Schoutenia furfuracea (Tiliaceae). Palms are also significant components with Oncospermum horridula being the most common species. Others such as Arenga obtusifolium, Eugeissona tristis and Iguanura wallichiana are also common, while Johannesteijsmannia altifrons and Orania sylvicola are more localised. Pinanga distichathe and the endemic Rhopaloblaste singaporensis (Arecaceae) are more frequent in the river valleys. Among the many lianas, common large woody species include Agelaea macrophylla, Ancistrocladus tectorius, Artabotrys suaveolens, Fagraea ridleyi, Indorochera griffithii, Milletia sericea, Rourea mimosoides and Tetracera scandens. The ground layer tends to have a patchy appearence but normally includes herbs such as Curculigo latifolia, Forrestia griffithii, Labisia pumila, Mapania cuspidata, Pentaphragma horsfieldia, Scrotochloa urceolata and the endemic or near endemic Hanguana malayana (Hanguanaceae). The forest floor is also the habitat to various ferns such as Pleocnemia irregularis, Taenitis blechnoides and the endemic or near endemic Tectoria singaporeana (Aspidiaceae). Malayan Riverine Forest In the Endau region these forests are characterized by an abundance of Ficus variegata, Dipterocarpus costatus, Shorea sinkgamang, the endemic palm Rhopaloblaste singaporensis (Arecaceae) and the endemic bamboo Racembambos setifera (Poaceae). Lianas are well represented by species of Bauhinia, Tetracera and the cucurbit Alsomitra macrocarpa, while the typical riverine shrubs are Pavetta indica and the endemic Ardisia tahanica (Myrsinaceae) and Phyllanthus watsonii (Euphorbiaceae). Bamboos and palms are also important. Typical bamboos include tall stands of Dendrocalamus hirtella and thickets of Gigantochloa ligulata and Schizostachyum latifolium, while common palms are Eleiodoxa conferta, Pholidocarpus kingianus and Salacca affinis. Common ground layer herbs are Catimbium assimilis and Scaphochlamys sylvestris. In most cases a distinct riverbank community can be distinguised. Here Tristania whitiana is the commonest tree Copyright © 2010 Peter Martin Rhind while other common ones include Glochidion rubrum and the endemic Dysoxylum angustifolium (Meliaceae). However, in the more swampy areas the overall composition changes with trees such as Ctenolophon parvifolius, Deplanchea bancana, Ganua motleyana, and Mussaendopus beccaiana becoming common together with spiny thickets of Fagerlindia fasciculata. On shady sections of riverbank the small endemic tufted fern Grammitis universa (Polypodiaceae) is common in rock crevices, while on sandy banks and bars a variety of pipeworts (Eriocaulon) make their appearance including the endemic Eriocaulon australe f. prolifera (Eriocaulaceae). Among the aquatic plants the endemic Cryptocaryne affinis (Araceae) can form extensive patches on shallow sand beds. Malayan Limestone Forests The enormous variation in Malayan limestone vegetation makes it difficult to summarize. At the base of hills a fairly tall, closed canopy forest can be found comprising trees such as Dendrocnide stimulans, Diospyros cauliflora Gmelina asiatica, Mallotus philippensis, Melanolepis multiglandulosa, Pisonia umbellifera and the endemic Orophea hirsuta (Annonaceae). The undergrowth is equally varied, but in the wetter areas where water drips down from the rocky slopes and overhanging cliffs, a distinct herbaceous ground layer including Alocasia lowii, Epithema saxatile, Monophyllaea horsfieldii the endemic Chirita caliginosa (Gesneraceae), and a luxuriant assemblage of bryophytes is often encountered. Moving on to the talus slopes the dominant trees are more likely to include Cleidion javanicum, Morinda elliptica, Strebulus ilicifolius, Trivalvaria macrophylla and the endemic Atalantia roxburghiana (Rutaceae). The herbs include Heterogonium pinnatum and a number of Impatiens species such as the endemic Impatiens mirabilis (Balsaminaceae). Where the slopes comprise boulder outcrops other endemic trees such as the rare Diospyros adenophora (Ebenaceae) and Polyalthia brunneifolia (Annonaceae) may become more conspicuous. Here the ground flora is usually sparse but may include several species in sheltered niches such as the endemic Gymnostachyum decurrens (Celastraceae). In the more sheltered gullies and valleys the typical trees and shrubs include Agrostistachys gaudichaudii, Canthium didymum, Randia densiflora, Sauropus suberosus, Sterculia rubiginosa and the endemic Fagraea curtisii (Loganiaceae). These locations also include several endemic palms such as Arenga westerhoutii and Iguanura polymorpha (Arecaceae). On the summits the vegetation is usually more scruby (2-7m tall), but the canopy typically remains closed and there may be several emergent trees such as the endemic Madhuca ridleyi (Sapotaceae). Other trees and shrubs usually include Cleistanthus gracilis, Decaspermum fruticosum, Eriobotrya bengalensis, Erythroxylum cuneatum, Garcinia minutiflora, Mallotus brevipetiolatus, Murraya paniculata, Neolitsea zeylanica, Sycopsis dunnii and several endemics such as Buxus malayana (Euphorbiaceae), Dehaasia curtsii (Lauraceae), Eugenia pendens (Myrtaceae), Glycosmis calcicola (Rutaceae), Pandanus irregularis (Pandanaceae) and Pistacia malayana (Anacardiaceae). Despite the shady conditions caused by the canopy there is comparatively rich ground flora with many bryophytes and ferns. The flowering plants may include Adenia nicobarica, species of Amorphophallus and the two endemic species Arisaema fimbriatum (Araceae) and Dichanthium mucronulatum (Poaceae). Malayan Heath Forest Characteristic of nutrient poor, shallow podzols, these forests are largely confined to the plateaux of Endau-Rompin and G. Panti with small patches on dry quartzite ridges such as G. Jerai. In Endau-Rompin they consist of small trees (6-8 m tall) with small crowns. Among the most abundant ones are Cotylelobium lanceolatum, Gluta aptera, Leptospermum flavescens and Tristania merguensis. The ground vegetation largely consists of the endemic or near endemic Styphelia malayana (Ericaceae) together with ferns such as Dipterus conjugata, Gleichenia microphylla and Matonia pectinata mixed Copyright © 2010 Peter Martin Rhind with Pandanus monotheca or Gahnia tristis. In some of the moister, open areas rattan such as Calamus holhumii and the endemic Calamus insignis var. insignis (Arecaceae) become more conspicuous. Also because of the low nutrient status of these forests there is a wealth plant species specializing in insectivory, myrmecophtism (ant-plant associations) and parasitism. These include insectivors like Nepanthes ampullaria, N. gracilis, and N. rafflessiana; myrmecophytes like Hydnophytum formicarium and Lecanopteris sinuosa and hemiparasites like Dendrotrophe umbellata and Macrosolen retusus. The environment also seems to encourage the develpment of tuber-forming epiphytes like Pachycentria maingayi. Malayan Mossy Forest Small stands of mossy forest can be found, for example, in the hills below the northern and northeastern rim of the Pandang Tremambun Plateau where the aspect and altitude is conducive to mist formation, which after rain envelops the side of the plateau. The area, which is strewn with boulders, supports a spindly forest of Gluta aptera, Rhodamnia cinerea, Symplocos adenophylla, the endemic Arthrophyllum alternifolium (Araliaceae) and tree ferns (Cyathea). As expected most of the rocks, tree trunks and exposed roots are covered with mosses, liverworts and filmy ferns. Other epiphytes include Ficus deltoides and Schefflera subulata. Malayan Ridge Forest Forest dominated by Shorea curtisii are well developed on the ridges of G. Beremban and G. Besar. Other large trees include Anisoptera megistocarpa, Cotylelobium lanceolatum, Heritiera simplicifolia,