Revision of the genus Aponogeton (Aponogetonaceae)

After the treatment of Jumelle in the Flore de Madagascar fam. 23 (1936) substantial additions were made and much material has accumulated. Instead of 7 species of Aponogeton distinguished by Jumelle, 11 are recognized in the present revision, among which 3 are new to science. Moreover it was found that the epithet of the laceplant — up till now fenestralis — has to be changed in madagascariensis. All names have been properly typified; all types could be examined by the author. Quite a few species were observed in cultivation, thanks to generous support from overseas. Special attention has been paid to a detailed examination of the seed structure and that of the embryo and also to flower dimorphism. Descriptions are given of all species and two keys are provided for their identification, one by several gross morphological characters and one based on the characters of the seed and embryo. No attempt has been made to provide a full bibliography of each species; this would have become very complicated by the fact that in former treatments not rarely sheets were assigned to species to which they do not belong. It appeared not useful to cite all these ‘sensus’ and ‘pro partes’. Of each species a distribution map was prepared. All examined sheets are enumerated in an identification list.