MORPHOLOGY AND TAXONOMY OF SURIRELLA OVALIS AND RELATED TAXA

Abstract

This is the first part of a comprehensive critical examination of the Pinnatae group in Surirella, dealing with the most abundant or most discussed taxa. Aided by LM and SEM comparisons with type materials, the diagnoses and usual concepts of various taxa have been verified, completed or revised. The observations include in particular: S.ovális Brébisson, S.ovata Kützing, S.crumena Brébisson, S.peisonis Pantocsek, S.brightwellii W.Smith, S.patella Kützing, S.minuta Brébisson and S.angusta Kützing. In addition we discuss a number of infraspecific taxa, questionable or confirmed synonyms and conspecificities with further taxa. Two races (‘Sippen’) are described as new taxa. One of them was found included in the syntype material of S. ovalis and in a sample with Brébisson's notation ‘Surirella ovalis’, and both have been confused with other established taxa until recently. These taxa can only be identified reliably if entire populations rather than single specimens are studied, on account of morphological variation occurring during the normal vegetative life cycle.