As partial requirement fulfilment for the Doctorate Degree in plant taxonomy

Abstract

An account of the diversity, distribution, and taxonomy of the Asteraceae in Sumatera is given, There are 133 species of74 genera in 11 tribes, New species are recoqnized in this study, Prenanthes L. (2 species), Senecio L. (1 species), and Emilia sonchifolia (L.) DC (1 variety). The tribe Heliantheae is the largest, with 28% ofthe total number ofthe genera, followed by Astereae with 15%, Inuleae 12%, Senecioneae 10%, Anthemideae, Eupatorieae and Lactuceae 8%, the' other tribes are represented by 4% or less, The most diverse genus is Blumea DC with 14 species. Other genera are only represented by 10 species or less, usually 3, or 2, or, more usually, by 1 species only. In terms ofindigenous and endemic species, Sumatera is richer than Java, There are 43 important weed species, which were introduced from tropical America, Africa, Asia and Europe. Among these Chromolaena odorata (L.) RM. King & H Rob. and Mikania micrantha Kunth are reported as the most noxious ones. Studies on 9 species of Vernonia Schreb, in Sumatera were conducted to find distinct characters to support their taxonomic delimitation. Foliar trichome types may have taxonomical value to delimit sections. However, further study on many more specimens form larger geographical areas such as Malesia is required combined with other investigations, i.e. chemotaxonomy, pollen morphology or DNA analyses to obtain a better idea for new proposals of redefinitions of the sections.