The process and morphology of conjugation in desmids, especially the genus pleurotaenium

Abstract

The process of conjugation is described for the desmid taxa Pleurotaenium ehrenbergii (Breb.) de Bary and P. trabecula var. mediolaeve (Piayf.) Krieger. Anomalous conjugations, resulting in parthenospores or triploid spores, are also described and the process of triple conjugation is illustrated. The exact nature of the conjugation vesicle, and its analogy but not homology with the conjugation tube of Zygnemaceae and some desmids, is discussed. It is suggested that there are two methods of conjugation in placoderm desmids and that the sequence of events described here for Pleurotaenium may be widespread. Two unique features of the Pleurotaenium zygospore are described, a morphologically- differented operculum and a mammillate mesospore. © 1972 Taylor & Francis Group, LLC.