Included here is the Malay Peninsula roughly south of the line between the Kedah River near Alor Setar on the west coast and Songkhlia on the east coast. The northern boundary therefore roughly crosses the border between Malaysia and Thailand.

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 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. 

References

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Wong, K. M., Saw, L. G. & Kochummen, K. M. 1987. A survey of the forests of the Endau-Rompin area, Peninsular Malaysia: principle forest types and floristic notes. Malayan Nature Journal, 41: 125-144.

Wyatt-Smith, J. 1959. Peat swamp forest in Malaya. Malayan Forester, 23: 5-32.