Chromosome counts in three species of Polysiphonia (Ceramiales, Rhodophyta)

Chromosome numbers are reported for three Polysiphonia species from Korea. Cytological investigation revealed the presence of 31 bivalents (N = 31) fo r P. harlandii Harvey, 28 bivalents (N = 28) for P. yendoi Segi, and 30 biv alents (N = 30) for P. decumbens Segi. The haploid number was found in vege tative cells and spermatia of gametophytes, and as bivalents in tetrasporoc ytes of these species. Results from this study support the view that the ba sic chromosome number for Polysiphonia is 30.