The Understorey Flora

The understorey flora of the Bau Limestone Area comprises at least 440 species in 189 genera and 74 families of flowering plants. The most speciose families are the Orchidaceae (132 species), the Rubiaceae (58 species) and the Araceae (41 species) with the Gesneriaceae, Zingiberaceae, Palmae, Moraceae and Urticaceae each with more than twenty species and for genera Ficus with 21 species and Schefflera, Piper, Cyrtandra and Hoya all with more than ten species. The calcifuge element is well represented with six species each for Medinilla and Vaccinium. The Bau Limestone Area shows high biodiversity associated with species restricted to limestone, most notably members of the Gesneriaceae and the Begoniaceae, many of which are endemic to the Bau or Kuching limestone. The distribution of narrow endemics confirms that the Bau Limestone Area is phytogeographically distinct from the Padawan-Serian limestone, which also falls within the Kuching Division. The limestone flora at Bau is endangered primarily by farming practices, which are widespread,as well as locally by quarrying.