About the key

This key arose as a component of six years of work by the authors to re-instate the use of diatoms for aquatic biomonitoring in South Africa. It contains information on 70 genera and 286 species, covering both the most common taxa, whilst also including key endemics.

Diatomology in South Africa has its origins chiefly through the work of the eminent Hungarian diatomist, Béla. J. Cholnoky. Cholnoky commenced his work in the early 1950s, first at the University of Pretoria and subsequently at the Council for Scientific and Industrial Research (CSIR) where he worked until his death in 1972. He published 38 articles, in which he described many hundreds of new taxa (Kiss, 2000), and a book dealing with the taxonomy and ecology of the diatoms of southern and central Africa (Cholnoky, 1968). Unfortunately, not to detract from his work, Cholnoky did not always adhere to the requirements of the international code of botanical nomenclature implemented in 1958 and, thus, many of his species are invalid until they have been re-investigated and validated (e.g. Taylor et al. 2010).

Cholnoky trained three algal specialists, R.E.M. "Archie" Archibald and Ferdi Schoeman specialised like their mentor in diatom taxonomy and ecology, while his brother, Colin Archibald, initially specialised in the study of blue-green algae or cyanobacteria, has in recent years also specialised in diatoms. Schoeman and "Archie" Archibald continued to work at the CSIR after the death of Cholnoky, and are perhaps best known in the diatom community for their Diatom Flora of Southern Africa (Schoeman & Archibald 1976), a work inspired by Cholnoky, and their seminal work on the group Amphora (e.g. Schoeman & Archibald 1984). Their collections reside alongside those of Cholnoky in the CSIR collection. Schoeman, together with Val Meaton, tackled the monumental task of ordering Cholnoky’s extensive collection and produced a complete catalogue of all of Cholnoky’s African material (Schoeman & Meaton 1981). Malcolm Giffen was a colleague of Cholnoky who lectured at the University of Fort Hare and collected diatoms from 1945 to 1976. He specialised, in the main, on marine littoral diatoms and also published on the freshwater flora of the Hog’s Back region in the Eastern Cape (e.g. Giffen 1963, 1966). His slides are also currently housed in the CSIR collection. The collection also contains much material donated from other collections such as the Hustedt collection.

After the untimely death of "Archie" Archibald, the diatom collection was championed by Colin Archibald and moved from CSIR Pretoria to the offices of CSIR Durban. The collection was ordered and housed and has been curated by Colin Archibald and Johan van der Molen until the end of 2009. During this time Bill Harding, briefly mentored by Archie Archibald during the early 1990s, investigated the collection and its contents in some depth during a Water Research Commission (WRC)- funded project, producing a report to show the scientific value and resources contained in the collection (Harding et al. 2004, 2005). Harding has continuously encouraged the full use and proper curation of the collection, as well as the integration of diatoms with aquatic biomonitoring in South Africa. The digitization process for endemic species started with an Andrew Mellon Foundation (USA) pilot project on fresh water Surrirelloid species, undertaken collaboratively with the National Botanic Garden of Belgium (Meise) and the Botanic Garden Berlin-Dahlem. The South African Biodiversity Information Facility (SABIF) recently funded a project lead by Johan van der Molen for the digitization of the collection catalogue and species information contained in the notes and publications of Cholnoky.

Recently Steve Mitchell (ex-WRC) brought various interested parties together to discuss the fate of the diatom collection, as the CSIR had indicated that it was not part of their mandate to curate a collection of national importance. This was in line with Harding’s original recommendation (Harding et al. 2005) that the collection should be actively-managed by an organisation better suited for this purpose (i.e. a national collections facility). The outcome of this process was that the ownership of the collection was transferred to the South African Institute for Aquatic Biodiversity (SAIAB). Part of the agreement for transfer was, however, that the collection would be housed and curated at the North-West University on the terms of a long loan. It was decided to proceed in this manner as SAIAB has a mandate to look after aquatic collections but no diatom expertise, while NWU is the current national centre for diatom research. The North-West University diatom collection of over four thousand samples was merged with the CSIR collection and together have become known as the South African National Diatom Collection.

The collection is now housed on the premises of the North-West University, Potchefstroom Campus and curated by Jonathan Taylor. Access to the collection has been available from January 2010 for the use of both South African and international scientists.

Parties interested in using the collection can contact the curator Dr. Jonathan Taylor on +27(0)18 299 1096/97 during office hours or [email protected].


Cholnoky BJ. 1968. Die ökologie der diatomeen in binnengewässern. Lehre: J Cramer.

Harding WR, Archibald CGM, Taylor JC, Mundree S. 2004. An Appraisal of the South African Diatom Collection. WRC Report No K8/508/2.
Water Research Commission. Pretoria.

Harding, WR, Archibald CGM and JC Taylor (2005) The relevance of diatoms for biomonitoring in South Africa. Water SA 31:41-46.

Harding WR, Archibald CGM, Taylor JC. 2005. Diatomology in South African biomonitoring: the South African Diatom Collection. Letter to the Editor. African Journal of Aquatic Science 30(2): 221.

Giffen MH. 1963. Contributions to the diatom flora of southern Africa. I. Diatoms of the estuaries of the Eastern Cape Province.
Hydrobiologia 21(3-4): 201-265.

Giffen MH. 1966. Contributions to the diatom flora of southern Africa. II. Diatoms from the Hog’s Back region of the Amatola Mountains,
Eastern Cape Province, South Africa. Nova Hedwigia Beih. 21:123-160.

Kiss KT. 2000. 100 éve született Cholnoky J. Béla, a "hazánkban elfelejtett" algológus (1899-1972). Botanikai Közlemények 86-87: 11-38.

Schoeman FR, Archibald REM. 1976. The diatom flora of southern Africa. C.S.I.R. Special Report WAT 50, Pretoria, South Africa.

Schoeman FR, Archibald REM. 1984. Amphora castellata Giffen as observed with the light and electron microscope. Bacillaria 7:113-134.

Schoeman FR, Meaton V. 1981. The B.J. Cholnoky diatom slide collection. C.S.I.R. Special Report WAT 59, Pretoria, South Africa.

Taylor JC, Van Staden W, Archibald CGM, Van Rensburg L. 2010. A re-examination of the type material of the diatom (Bacillariophyceae)
Cymbella kappii
(Cholnoky) Cholnoky. Polish Botanical Journal. 55 (1): 119-126.