Floristic and vegetation studies of Lao PDR (Lao People’s Democratic Republic) are uncommon. Understanding the floristic characteristics and affinities of Laos is important for understanding the plant geography of the Indochina peninsula.

  Prof. ZHU Hua of Xishuangbanna Tropical Botanical Garden (XTBG) completed an updated list of native seed plants in Laos PDR based upon entries in the checklist of the vascular plants of Lao PDR. He analyzed the floristic patterns and geographical elements of Laos and examined its floristic affinity to neighboring countries. He also discussed biogeography of the Indochina peninsula.

  A revised list of native seed plants from Laos PDR is presented comprising 5,005 species in 1,373 genera and 188 families. Geographical elements show that the families with tropical distribution contribute 62.23% of the total sum of the flora including flora with pantropical distribution (42.02%).

  The genera with a tropical distribution contribute 82.30%, in which the genera of tropical Asia make up 30.08%. This reveals that the flora of Lao PDR is tropical in nature and has a conspicuously tropical Asian affinity.

  The flora of Laos has similar floristic composition and geographical elements to its neighboring countries from the Indochina peninsula and belongs to the same biogeographical unit.

   Compared with other Indochinese countries, the flora of Laos has the highest similarity with the flora of Vietnam (92.13% at the generic level and 61.19% at the specific), followed by Myanmar at the generic level and Thailand at the specific level.

  The study entitled “Floristic characteristics and affinities in Lao PDR, with a reference to the biogeography of the Indochina peninsula” has been published in PLoS ONE.