Seven genera of pitcher plants namely Cephalotus, Heliamphora, Darlingtonia, Brocchinia, Nepenthes, Sarracenia and Catopsis. Pitcher plants have a worldwide distribution . Nepenthes is the largest genus belonging to the family Nepenthaceae and consists of 120 species and five incompletely described taxa in seven geographical groupings: Nepenthes of Peninsular Malaysia and Indochina, Nepenthes of Borneo, Nepenthes of Sulawesi, Nepenthes of Sumatra and Java, Nepenthes of the Philippines, Nepenthes of New Guinea and Maluku Islands, and lastly Nepenthes of the Outlying Areas . The endemic species of Nepenthes occur throughout Southeast Asia, particularly in the Sunda region, which includes Borneo, Sumatra, the Malay Peninsula, Java and some of the southern islands of the Philippines .
The Nepenthes flora in Peninsular Malaysia is relatively poor with only 11 species presently recorded (N. alba Ridl., N. albomarginata T. Lobb ex Lindl., N. gracillima Ridl., N. ampullaria Jack, N. benstonei C. Clarke, N. gracilis Korth., N. macfarlanei Hemsl., N. rafflesiana Jack, N. mirabilis (Lour.), Druce, N. ramispina Ridl. and N. sanguinea Lindl.). In comparison, there are 36 species recognized in Borneo, representing the greatest diversity of Nepenthes species in Southeast Asia [1, 3]. Clarke  reported only ten species of Nepenthes in Peninsular Malaysia, classifying N. alba as a heterotypic synonym of N. gracillima. Four of these species are restricted to montane habitats (N. macfarlanei, N. gracillima, N. sanguinea, N. ramispina), two species are found mainly on low hills (N. albomarginata and N. benstonei) and another four are lowland species (N. ampullaria, N. gracilis, N. mirabilis and N. rafflesiana). McPherson  described both N. alba and N. gracillima as distinct species.
The taxonomy of Nepenthes is based primarily on morphology (shape, color, size and ornamentation) [1–6]. Jebb and Cheek  recognized a single species, N. vieillardii, in New Caledonia into a single species, even though several species were recognized based on morphological variation. Kurata et al.  clarified the morphological diversity and verified the species classification of N. vieillardii, and they tentatively supported the taxonomic classification based on the pitcher morphology by Jebb and Cheek . The current classification of Nepenthes in Peninsular Malaysia is also based on morphological characteristics, with distinct differences apparent between species found at high, intermediate and low altitudes.
Previous molecular phylogenetic studies of Nepenthes based on chloroplast (trnK intron and matK gene) and nuclear (PRT1 and a translocated copy of trnK) sequences have provided a well-supported phylogeny of many species [9–11]. Using the plastid trnK intron in phylogenetic reconstruction, the three lineages can be separated according to habitat . The first lineage included all species found in Sumatra, the Malay Peninsula and the Southeast mainland; the second lineage consisted of the species from Sulawesi, Borneo and the Philippines; and the third lineage comprised Nepenthes from New Guinea and Sulawesi [9, 11]. Meimberg and Heubl  also suggested that biogeographic “outlier species” occurring in Seychelles (N. pervillei Blume.), Sri Lanka (N. distillatoria L.), Madagascar (N. madagascarensis Poir. and N. masoalensis Schmid-Hollinger) and India (N. khasiana Hook. F.) are related to the three lineages consisting of all taxa from the Indo-Malay region.
Apart from molecular phylogenetic studies of Nepenthes using nuclear PRT and plastid matK DNA sequences [9–11], there has been little development in the molecular systematics of Nepenthes. We report here the potential of the plastid trnL intron and nuclear ITS DNA sequences for the phylogenetic inference of Nepenthes in Malaysia. We also report here the phylogeographics of the Nepenthes species found in Peninsular Malaysia based on the DNA sequence data.