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.