Sunday, 29 March 2009

Hibiscus diversity

It is not clear what the appropriate bounds for the genus Hibiscus are, Bernard Pfeil and coworkers having found that several genera (including the large genus Pavonia) are nested within Hibiscus, and Margaret Koopman having found that a clade consisting of some Malagasy species of Hibiscus and some endemic Malagasy genera is the sister group to the rest of Hibiscus and its embedded genera. However, I have been building a list of Malvaceae species of the world, and my tally for Hibiscus, under the Kubitzki and Bayer circumscription (I'm approproaching the point of grasping a couple of nettles and sinking Symphochlamys and Macrostelia), has reached approximately 400 species, which exceeds the figures usually given in the literature (300 is the upper bound of the numbers I've seen). This would make Hibiscus comfortably the largest genus in the family, well ahead of Abutilon, Sida, Pavonia and Sterculia. For individual sections I now have a tally of 79 species for Bombicella, and 107 for Furcaria (estimates of species diversity for this section run up to 150 species). No other section has nearly as many species as these, but between them all, and the nearly 100 species for which I haven't seen sectional affiliations the total of 400 is reached. I've written up short web pages on sections Bombicella and Lilibiscus