Molecular and morphological characters distinguishing two porphyra species (rhodophyta: Bangiophycidae)

Abstract

Definition of species limits within the rhodophyte genus Porphyra is hampered by the lack of reliable morphological markers; confusion in the taxonomy has serious implications for ecological studies. We report the results of a combined morphological and molecular analysis of plants variously referred to as P. purpurea, P. purpureo-violacea, P. umbilicalis f. laciniata and P. laciniata. All plants examined fell into one of two distinct groups: P. purpurea—monoecious with reproductive fronds divided into two distinct, but often unequal, male and female parts; P. laciniata—dioecious with fronds folding in half longitudinally when hanging vertically. All plants within a group were found to share a common nucleotide sequence for the chloroplast-borne rbcL-S spacer; a single nucleotide transition separates the two groups. © 1996 The British Phycological Society.