PLOIDY VARIATION IN THE GROUP OF MYOSOTIS-PALUSTRIS AND M-LAXA IN THECZECH-REPUBLIC AND SLOVAKIA

In 74 natural populations of the Myosotis palustris and M. laxa groups from former Czechoslovakia three euploid and one aneuploid cytotypes were found that belong to the following species: M. nemorosa BESSER, 2 n = 22, M. palustris (L) NATH. em. REICHENB. in STURM, 2n = 66, M. lax iflora REICHENB., 2n = 66, M. radicans OPIZ, 2n = 66(64), M. breviseta cea (SCHUSTER) HOLUB, 2n = 66(64), and M. caespitosa C.F. SCHULTZ, 2n = 88. With the exception of M. nemorosa, the chromosome numbers are pu blished for the first time for the Czech Republic. The chromosome numb ers, 2n = 66, 2n = 64 are found in M. brevisetacea, are new for the li terature. The correlation between pollen size and ploidy level has bee n studied as well, and statistically significant differences were foun d between cytotypes belonging to different ploidy levels.