KARYOLOGY OF BANGIA ATROPURPUREA (RHODOPHYTA,BANGIALES) FROM MEDITERRANEAN AND NORTHEASTERN ATLANTIC POPULATIONS1

We studied the karyology of Bangia atropurpurea (Roth) C. Ag. collected from marine and freshwater populations from the Mediterranean region and some northeastern Atlantic localities. Gametophytic thalli had two haploid karyotypes, n = 3 and n = 4. The n = 4 karyotype was only occasionally present in the Mediterranean and was also found in one Atlantic population, confirming a previous report. We propose that the four-chromosome karyotype is an aneuploid form, n + 1. Chromosomes were frequently observed either in a parallel arrangement or in a circular configuration.