Desmids are microscopic single-celled green algae with a typical symmetrical appearance. The cells are divided in two halves ('semicells') that are mirror images of each other and show a remarkable variation in shape and ornamentation. Because desmids thrive in clear and nutrient poor freshwater, they gain increasing attention from ecologists for assessing and monitoring wetland areas.

The objective of this site is to illustrate all of the desmid species in the world. At this moment this collection consists of digital images of desmids taken from samples from Europe, North-America and Africa. Material can be fresh or fixed, but this is not indicated in the text. New taxa are added on a irregular basis and existing images can be changed by better ones. Be aware that pictures of desmids and micrometers can scale differently on a printer, so measurements are better be taken on the screen.

Identifying desmids is a time-consuming business, because taxonomic literature is hopelessly scattered about and difficult to purchase. For that reason most specimens are not identified with the original descriptions, usually published in separate articles, but with the more comprehensive monographs and floras. A summary of these books, besides other information about desmids, can be found at the site of the Dutch Desmid Club. In those cases where the larger works did not provide a satisfactory answer, 'loose' publications were consulted.

Last updated: January 27, 2012 (Revision history)