The Rubiaceae of Ko Chang, south-eastern Thailand

Ko Chang is the second largest island of Thailand. Its Rubiaceae were first treated by K. Schumann in Schmidt's Flora of Koh Chang. He recognised 55 species in 27 genera. Based on herbarium and field work, 64 taxa belonging to 33 genera are currently recorded. Although the numbers of taxa in Schumann's treatment and ours do not widely differ, there are major changes in status of the taxa. Eight of the 27 generic names in Schumann's treatment are no longer applicable; only 20 of the 57 taxa names are still in use. Of the 10 species newly described in the Flora of Koh Chang, only one is a good species; none of the new combinations have been maintained. Fifteen taxa have been newly recorded since Schumann's treatment. The relatively large proportion of rubiaceous taxa showing a Ko Chang (or general south-eastern Thailand)/ peninsular Thailand disjunction is remarkable.