He is actively involved on environmental issues, a trustee of the Amazon Charitable Trust, and a Vice-President of the Nature in Art Trust.
In a foreword, Kew Gardens Director Ghillean Prance notes that here we have the unusual complete taxonomic study (nowadays) of a large and complex genus, but also a genus which is global in extent.
Professor Sir Ghillean Prance, British botanist and ecologist, former Director of the Royal Botanic Gardens, Kew