The morphological range in Mallotus (Euphorbiaceae) and a taxonomic revision of its section Rottleropsis (including Axenfeldia) in Malesia, Thailand and Africa

The range of diagnostic morphological features in the whole genus Mallotus is reviewed as background to the taxonomic treatment of section Rottleropsis s.l. Special emphasis is given to the indumentum, habit, stipules, leaves, extrafloral nectaries, domatia, inflorescences, flowers, pollen and fruits. Notes on the geographical distribution, ecology, pollinators, fruit and seed dispersal, and uses of the genus are also presented. The section Axenfeldia is reduced to sect. Rottleropsis on account of the absence of suitable morphological characters to distinguish them. A taxonomic revision of 38 species of sect. Rottleropsis s.l. from Malesia, Thailand and Africa is presented, together with regional and synoptical identification keys, distribution maps and illustrations. Four new species are described: Mallotus connatus, M. longinervis, M. minimifructus and M. mirus. Several non-Malesian species not included in this revision are briefly discussed. This paper concludes a series of taxonomic revisions of the genus Mallotus in Malesia and Thailand.