A Monograph on Some British Desmids

Desmids are freshwater green algae appearing to be a pair of joined cells (hence their name derived from the Greek desmos meaning a bond or chain) but in fact made up of two characteristic half cells (semicells). They have considerable diversity in their external morphology and are the largest of the unicellular plants, allowing them to be easily handled and cultured. This enables their use in studies of morphogenesis, physiology and genetics.
Desmids have very considerable morphological variability (polymorphism) and a given species can exhibit a range of growth forms. Consequently, many forms have been given taxonomic status by earlier workers. This volume provides descriptions which take into account adequately the range of variation that can be expected for each species in the populations studied by the authors; unlike the descriptions, in many cases, provided by earlier workers.
This volume has been produced to reflect the considerable changes in desmid taxonomy and systematics together with the additional knowledge now available on desmid distribution and ecology in the British Isles. It provides dichotomous keys for the identification of the 100 or more species and varieties of the 7 saccoderm (the subfamily Mesotaenoideae) and 4 placoderm genera (from the families Peniaceae and Closteriaceae) described, together with information on their distribution and ecology in the British Isles. The introductory material deals with the recent changes in desmid taxonomy and systematics, the habitats where desmids occur together with collection, preservation and examination methods.