New taxa to commemorate the opening of the Van Steenis building by Her Majesty Queen Beatrix

Systematic botany is about the discovery, description, naming, and understanding of plant diversity. Of these four aspects the naming and describing of new species belongs to the most traditional, yet exciting activities of the plant taxonomist. On the occasion of the official opening of the Van Steenis Building by Her Majesty Queen Beatrix, we indulge in presenting species and one genus, new to science, and named to commemorate this auspicious event. The Van Steenis Building provides the new and highly functional premises for the Rijksherbarium, the Centre for Environmental Science, and the facilities for the undergraduate study of biology of Leiden University. Prof. Dr. C. G.G.J, van Steenis (1901-1986) was an unrivalled authority of Malesian botany but he also was a pioneer in tropical vegetation science, ecology and nature conservation. During his directorship of the Rijksherbarium (1962-1972) the institute flourished as never before. The moss species Dicranoloma steenisii Klazenga is named in his honour, and adds another taxon to the rich eponymy commemorating this great botanist. We are very honoured that his widow, Mrs. Van Steenis-Kruseman will be present at the opening ceremony. It may seem ironic that the inauguration of the building which carries Van Steenis’s name is celebrated with the launching of new taxa. The credo of Van Steenis was that we should endeavour to determine how few, not how many species are comprised in the flora of a region. Of course he was absolutely right in criticising the light-hearted description of new species on the basis of slightly deviating plant specimens. The new taxa presented here have nothing in common with these ephemeral blemishes on botanical nomenclature; they are good and distinct species recognised by specialists from the ‘Leiden School’, who are renowned for their tendency to lump rather than to split.