The Sumatran Genus Morinda L. (Rubiaceae)

Abstract

The major revision of the genus Morinda for the Sumatran region was undertaken by Miquel in 1856 and 1862 but there has no comprehensive revision of the genus recently. Therefore the revision of the genus in Sumatra was done based on their morphological characters, especially to know the species of Morinda and their distribution pattern. A phylogenetic analysis was also studied to establish the relationship among the species using parsimony analysis. The present study revealed that there were eight species, six species among them were previously known as M. citrifolia L., M. jackiana Korth., M. leparensis Valeton, M. rigida Miq., M. tomentosa Roth, M. umbellata L., and two newly proposed species namely M. lanuginosa Suratman and M. wongiana Suratman. M. bracteata Roxb. var. latifolia Valeton was also proposed as the new synonym of M. citrifolia L. var. bracteata (Roxb.) Hook.f. An identification key and detailed description of the taxa were provided. The natural history data including habitat, distribution, uses and vernacular names were also presented. The most widespread species is M. citrifolia while the other species have a limited distribution. The highest number of the species is found in North Sumatra and Bangka Belitung which consist of 4 species respectively. The phylogenetic analysis based on morphological data showed that despite their poorly resolved phylogenetic tree, Morinda is undoubtedly a monophyletic genus.