Imperfect Forms and the Taxonomy of Mallomonas

This paper deals with taxonomic problems caused by the occurrence in nature of forms of Mallomonas species which are considered to be stages in development. They are called ‘imperfect ’ forms; that is, forms that lack features that have been included in the diagnosis. These individuals might be described as separate species except when intermediate forms are noticed which link them with the perfect form of diagnosed species. The fine details of their scales are the same as in the perfect form