EN
Differential staining of constitutive heterochromatin was used to investigate the karyotype of Pleurozium schreberi (n = 5), the object of Vaarama’s (1954) classic work. C-banding demonstrated that the haploid karyotype is heterochromatin-rich. The total amount of heterochromatin is 44.1% of the karyotype length. Telomeric as well as intercalary bands were observed in particular chromosomes. Centromeric bands were recognized in one chromosome only. The banding pattern of chromosome A, the longest, largely resembles Vaarama’s description. Heterochromatic bodies were also observed in interphase nuclei.