A word about names
The family Cactaceae is a group of plants which is undergoing a rapid evolutionary radiation. This means that plants are adapting to their various environments rapidly (in evolutionary terms), and new species are in the process of forming. It is often very difficult to decide what is a different species from another when there is a gradual change in appearance from one to the other over a geographical area. On top of this, new plants and varieties are being discovered all the time, as each new remote valley of the Andes is explored by botanists.
With the genera Aylostera, Rebutia and Weingartia, there has been a great deal of argument as to which plants were related to which others, and as a result much argument about what individual plants should be called, and whether or not plants are full species, subspecies, or just varieties of others. Here at this collection we have adopted, for the moment, two recent studies which have compared the features and the DNA of currently known plants, backed up by extensive fieldwork. These studies (one for Aylostera and Rebutia, including Mediolobivia, and one for Weingartia, including Sulcorebutia and Cintia) have been relatively well received by the establishment and give us a good framework to base our labelling and cataloguing. We will of course try to keep up to date with any new studies that are produced.
Some external resources: