Chromosome numbers for fifteen species in the genus Porphyra (Bangiales, Rhodophyta) from the west coast of North America

Abstract

A list of chromosome numbers for fifteen species of Porphyra from the west coast of North America is presented. The basic haploid number found in vegetative cells of the foliose thallus and beta-spores is three, although numbers from two to five are found in some species. Diploid chromosome numbers were determined during divisions leading to alpha-spore formation in four species. Chromosome numbers have been recorded for the vegetative cells of the conchocelis phase of seven species; four are haploid and three diploid. Implications of these data in systematics are discussed.