Dermatolithon litorale (Suneson) Hamel & Lemoine (Rhodophyta, Corallinaceae) in the British Isles

Abstract

D. litorale is a distinct species in the British Isles and closely resembles other European material of the same species which is known only in the bisporangial phase throughout its range. It is distinguished from D. pustulatum by its colour, its thinner thallus, and the size, shape and surface structure of its conceptacles. Shore observations over 2½ years have not revealed a seasonal pattern of occurrence; they do suggest that, where present, it remains in small quantity until local conditions particularly favour its growth when it is able to increase very rapidly to become abundant. The germination of its bispores agrees well with spore germination patterns in other species of Dermatolithon. Previously this species has been tentatively synonymized with other species reported from India and Pacific North America. On the basis of present knowledge it is suggested that these species are not in fact the same taxon.