On morphological distinctions of some species of Pacific North American Laurencia

Abstract The anatomy of four species of Californian Laurencia (Rhodophyta, Rhodomelaceae), L. spectabilis, L. splendens, L. blinksii, and L. crispa is described, and their morphology is discussed and compared with Japanese species of the genus. The “Spectabilis Group”, comprising six species of Pacific North American Laurencia, is preliminarily proposed as containing taxa showing characteristics of male and tetrasporic plants which are different from those of other groups of species.