Rubiaceae of Madagascar

The Rubiaceae comprises about 8% of the flora of Madagascar and remains the largest family without a modern treatment. It represents a major component of most vegetation types, particularly humid forests, and this project will facilitate diversity studies and conservation management across the island.

Searching for Rubiaceae specimens in Western Madagascar. Photo © M. Briggs.

The Rubiaceae of Madagascar project started in 1997, with the goal of producing an accelerated survey for the Rubiaceae of Madagascar. There were originally five product-linked objectives: (1) an identification manual to genera; (2) a specimen database to be used with a Geographical Information System (GIS) to investigate plant diversity and distribution patterns for conservation planning; (3) a provisional checklist to species; 4) an interactive specimen database; (5) taxonomic revisions of selected groups (with a focus on Coffea). 

Achievements. The identification manual to genera is ongoing, with further morphological study and molecular investigation required before completion. It is our intention to publish this part of the project as A Guide to the Rubiaceae of Madagascar. This book would be a collaborative venture between RBG, Kew and international partners. The identification guide thus far has been compiled from comprehensive literature review, fieldwork, study of herbarium specimens, and original research (morphology and molecular systematics). The book will include descriptions of c. 90 genera, identification keys, distribution maps, and a checklist to approximately 800 species.

The specimen database with GIS interface became operational in 1998 and since then has been of considerable value as a dynamic resource for providing baseline conservation data on threatened species and areas. The specimen database was constructed using herbarium specimen label data, entered from specimens housed at the herbaria of Kew (K), all types and selected groups from Paris (P), Geneva (G), Antananarivo (TAN, TEF), Missouri (MO), and other miscellaneous herbaria. Approximately 17,000 specimen records have been captured in the database.

The draft version of the taxonomic revision of Coffea in Madagascar was completed during the course of the project, despite finding twice as many species than estimated in the original proposal. We have discovered more than 20 species new to science, 17 of which have already been published. The publication of the taxonomic revision of Madagascan Coffea was suspended pending molecular investigations into the delimitation of the genus Coffea and this work has now been completed. The Coffees of Madagascar ― A regional monograph of the genus Coffea L. in Madagascar and the Comoros (Davis & Rakotonasolo) is in preparation. Revisions of several other genera have been completed, including Gardenia, Bertiera and Flagenium.

The main focus for the Rubiaceae of Madagascar project for 2011 onwards is the completion of taxonomic revisions for Coffea, Psydrax, Rytigynia, Psychotria, and other selected genera, in collaboration with partner institutes.