This BioProvince (as defined by Armen Takhtajan) comprises the central and southern parts of Annam in central Vietnam and the adjacent regions of Laos. However, recently a central Annamese biozone and a southern Annamese biozone have been recognised but here these are regarded as subprovinces. The central subprovince comprises the central part of the Truong Son Range, which includes a number of plateaus such as Kontum and Playcu in Vietnam and Boloven in Laos. The Mekong River basin and the basins of the Kong, San, Srepok and the Da Rang rivers, form the western and southern boundaries. The area also embraces a few islands in the South China Sea and Hoang Sa atoll archipelago. The southern subprovince includes the extreme southern portion of the Truong Son or Annamite Range, while plateaus here include the lam Vien (Dalat), Mo Nong (Djiring) and Di Linh. The lowlands of the Mekong, Krong, Ana and Da Rang river basins form the southern, western and northern boundaries. Much of the area as whole lies on a basement of ancient crystalline rock composed of Precambrian gneiss often covered with highly metamorphosed continental and marine sediments. Although no folds exist in the base rock it was dissected and divided into a number of uplifted blocks during Palaeozoic and Mesozoic orogenetic movements. Today there are a number of mountain massifs that were formed by various granite intrusions during the late Mesozoic period. Scattered throughout the area are the eroded remains of ancient volcanoes. The climate varies from monsoon tropical with cold winters in the northwest to monsoon tropical with warm winters in the south. The flora comprises several endemic genera including Indosinia, Oligoceras and Poilanedora and a number of endemic species including several endemic cycads such as Cycas micholitzii.
The following accounts for this BioProvince have been written or will be written with particular reference to endemic and locally important species. Accounts available are displayed in green or yellow. Those displayed in red are either in the pipeline or awaiting expert contributions.
|Endemic Vascular Plant Flora|