Abstract
1. Distinct polyploidy is found in four forms of freswhater C. glomerata. Its forms constitute a polyploid series based on the chromosome number of 12; which are shown as follows:
C. glomeyata (L.) Kütz. is octaploid, 8n=96.
C. glomeyata forma genuina is hexaploid, 6n=72.
C. glomerata forma Callicoma is tetraploid, 4n=48.
C. glomerata subforma Kiitzingiana is tetraploid, 4n=48.
2. The chromosome counts reported by Geitler (1936) in a form of C. glomeyata, and by Schüssnig (1954) in another form of C. glomerata are confirmed.
3. The size of polyploid nuclei is larger than the haploid and diploid ones, and the maximum number of nucleoli varies directly with the degree of polyploidy.
4. A correlation between the number of chromocentre-like bodies, and the number of nucleoli has been observed and an association between these two structures is particularly observed in forms of C. glomeyata. The chromocentre-like body may therefore represents a nucleolar organising region of a chromosome.
5. Polyploidy is found only in freshwater species; the marine species being diploid (Sinha, 1963 and 1965).
6. The detailed morphological characters of four forms of C. glomeyata have been studied. Photomicrographs have been produced in support of the evidence of the presence of nucleoli, associations of chromocentre-like bodies with nucleoli and the mitotic chromosome counts. The method of staining by acetocarmine has been used for cytological study.
