Systematics and biogeography of Phyllanthus (Phyllanthaceae) of Madagascar

A systematic and  biogeographical study of the fifty five species of the genus Phyllanthus (Phyllanthaceae) which occur in Madagascar and the Comoro Islands.

 Phyllanthus fuscoluridus Photo: H. Ralimanana.

Kew's collaborative work in Madagascar has a long tradition. This project is one of the first three PhD projects in Botany carried out at the University of Antananarivo, with joint supervision from RBG Kew, and it is hoped that the results of this research will serve as a model for future Malagasy researchers who wish to pursue a career in plant systematics.

The results of the study will form the basis for the treatment of the genus Phyllanthus (Phyllanthaceae) in the new edition of Flore de Madagascar et des Comores. Fifty five species grouped in nine subgenera have been recognised, of which forty six species are endemic to Madagascar and one (Phyllanthus comorensis Leandri) is endemic to the Comoro Islands. Five of the nine subgenera are newly described, or validated from Brunel (1987)

The project is also part of a wider phylogenetic study (see Molecular phylogenetics of tribe Phyllantheae (Phyllanthaceae). Phyllanthus is one of the largest angiosperm genera (c. 1200 species) with complex internal relationships. In order to understand it, it first has to be studied at floristic level. Field trips to different parts of Madagascar and the Comoro Islands have not only yielded herbarium collections and valuable ecological and geographic information, but also a large number of silica-dried leaf specimens to be used in DNA sequence analysis. In return, the molecular phylogenetic study has assisted greatly in assessing intrageneric placements of the Madagascan species.

Outputs are, besides the aforementioned collections: a revised taxonomic account with full morphological descriptions produced from a DELTA database of all available characters; a species identification key for staminate and pistillate plants; full synonymy and typification; distribution maps produced with GIS software; notes on ecology and uses as well as IUCN conservation ratings. Many of these methods are new to botanical research in Madagascar

In the course of this project, Hélène Ralimanana has consulted the herbaria of TAN and TEF in Madagascar and those of BM, K, LINN and P in Europe. She has given a presentation at the AETFAT conference in Addis Ababa in 2003 and co-authored several Phyllanthaceae research papers. Hélène was awarded her doctorate in 2007 and has submitted two papers on her PhD work for submission to English-language international journals, whilst her thesis is written in French. She is presently preparing two further papers on her work.