249 Malayan Nature Journal 2010, 62(3), 249-306 The flora of Tasik Bera, Pahang, Malaysia A. R. RAFIDAH 1 , M. Y. CHEW, A. R. UMMUL-NAZRAH and S. KAMARUDIN A botanical inventory of the plant communities at Tasik Bera, Pahang covered a mosaic of habitats, namely, open water, rassau swamp, Lepironia reed-bed, seasonal freshwater swamp forest, and the surrounding lowland dipterocarp forest, and resulted in an annotated checklist of 807 species of vascular plants in 400 genera and 128 families. The checklist includes previous collections. The largest family was Euphorbiaceae (24 genera, 59 species), followed by Dipterocarpaceae (6 genera, 58 species) and Rubiaceae (31 genera, 56 species) and the largest genera were Shorea (20 species), Syzygium (14 species) and Dipterocarpus and Hopea (both with 11 species). Keywords. Tasik Bera, Pahang, plant checklist, rassau swamp, Lepironia reed-bed. INTRODUCTION Tasik Bera is the largest natural freshwater lake in Peninsular Malaysia. It is situated in SW Pahang near the Negeri Sembilan border between 3º00'–3º10' N and 102º33' –102º39' E in the low-lying, undulating plain between mountains of the Main Range in the west and hill ranges to the east. The much-branched lake and swamp system is at an altitude of 30–35 m while the surrounding low hills attain an altitude of about 80 m. The wetland itself covers over 6,800 ha, measuring about 35 km by 25 km. The 61,000 ha catchment is the watershed for two river systems: the northward- flowing Sungai Bera joins Sg. Pahang and drains into the South China Sea, while the southward-flowing Sg. Palong joins Sg. Muar and drains into the Straits of Malacca (Fig. 1). Access to Tasik Bera is only via a few traditional entry points: from the Ramsar site management office at Tanjung Keruin in the north; from Pos Iskandar (in the southern half of the lake); and Kampung Pathir (NW of Tanjung Keruin). Tasik Bera has been inhabited by the indigenous Semelai people for over 600 years. Their settlements are scattered around the edge of the swamp. They engage in shifting cultivation, hunting and fishing. Tasik Bera is surrounded by freshwater swamp forest. Due to the impeded drainage, runoff from the surrounding area is captured in the lake and organic 1 Forest Research Institute Malaysia, 52109 Kepong, Selangor, Malaysia. rafidahar@frim.gov .my Manuscript received: 5 Jan 2010 Manuscript accepted: 10 May 2010