Sumatra and Peninsular Malaysia are both part of Sundaland together with Borneo and Java. Vegetation studies by Laumonier (1990, 1997) show the Sumatra flora is most similar to that of the Peninsula (sharing 49% of species) compared with those of Borneo (45%) or Java (37%). From the literature, opinions about the Sumatran flora seem contradictory. On the one hand, Van Steenis (1987) noted the peculiarity of the low number of endemic genera in Sumatra, 13, compared with 24 in Peninsular Malaysia (Johns, 1995). On the other hand, Sumatra boasts one of the two Malesian endemic families, the Pentastemonaceae, while the Peninsula has none.