A Molecular and Morphological Analysis of Microthamnion (Chlorophyta, Microtharnniales)

Summary Genomic relationships of the microphytic green alga Microthamnion isolated from a wide range of habitats in different geographical locations were examined by means of restriction enzyme analysis of amplified nuclear-encoded 18S rRNA genes. Restriction fragment patterns obtained using six endonucleases were identical in the 29 clonal strains investigated. A recent review ( John & Johnson 1987) of morphological variation in the genus has concluded that it is either a complex of at least two species (separated on dimensional characters), or a single very polymorphic species. The consensus between the analysis and the morphological data supports the view that Microthamnion is monospecific.