About us

The SSK was founded in April 2004 by a group of cactus enthusiasts from Germany, The Netherlands, Denmark, Austria, Switzerland and the USA. Our ambition is to contribute to the clarification of genetic relationships of popular South American cactus genera with objective methods. To achieve this, it is essential to cooperate with scientific institutions. This rather seldom collaboration of enthusiasts and qualified molecular biologists has yielded remarkable results within a short period of time.
The cactus lovers profound knowledge of populations and their habitats could be incorporated in professional research and contribute to the documentation of biodiversity.

Cacti received comparatively little attention in molecular plant systematic. The current classification is based on morphological characteristics. This subjective character weighting tendentiously leads to an unrealistic increase of species numbers. Especially in the last decade the pleasing number of newly discovered populations has led to description of species, which cannot be explained plausibly by known geological, paleoclimatic, and ecological parameters of speciation. On the other hand, such development can tempt to combine taxa for the sake of clarity, which do not share a reasonable close genetic heritage. This applies particularly to the popular small globular genera.

So far we have focussed on phylogenetic relations of Gymnocalycium, Rebutia (sensu Backeberg), Sulcorebutia, and Weingartia. The three latter genera are combined in the current classifications into Rebutia, although their biological relationships are still controversially discussed. For Gymnocalycium, Sulcorebutia, and Weingartia genetic proximity has been assumed for many years. In the meantime we could clarify a part of the questions with DNA sequence analysis. At present we examine the infrageneric relations of Sulcorebutia and Weingartia with the AFLP Fingerprint method. Please visit our project pages for further information.

Our members enjoy a rather wide scope of interests and different approaches to the topics. For the time being we do not advance a common view about species and genera but deliberately afford diversity of perspectives as long as we cannot present consolidated findings from our investigation. For this reason not every publication that refers to our projects reflects an SSK view. It exclusively represents excluding the opinion of the authors.

Our study community is a non-profit association. Our projects are financed by bounties of our members and other interested cactus lovers. Our legal status of "Public Utility" allows inclined donators to set off their contributions against tax liability (at least in Germany). In the accounting years 2004 - 2006 our projects were financially supported by the German Free State of Thuringia (Thüringen).

Weingartia steinbachii Weingartia steinbachii Gymnocalycium armatum Gymnocalycium armatum Weingartia pulchra Weingartia pulchra

Weingartia steinbachii

Gymnocalycium armatum

Weingartia pulchra

All photos on this Website © Ingrid&Rainer Mecklenburg

Study Community of South American Cacti