MOLECULAR AND MORPHOLOGICAL CHARACTERS DISTINGUISHING 2 PORPHYRA SPECIES (RHODOPHYTA, BANGIOPHYCIDAE)

Definition of species limits within the rhodophyte genus Porphyra is h ampered by the lack of reliable morphological markers; confusion in th e taxonomy has serious implications for ecological studies. We report the results of a combined morphological and molecular analysis of plan ts variously referred to as P. purpurea, P. purpureo-violacea, P. umbi licalis F. laciniata and P, laciniata. All plants examined fell into o ne of two distinct groups: P, purpurea-monoecious with reproductive fr onds divided into two distinct, but often unequal, male and female par ts; 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-bome rbcl.-S spacer; a single nucleotide transition separates the two groups.