Chromosome number variation in the genus Rubus in the Czech Republic. I.

Chromosome numbers are presented in 20 species of the genus Rubus subgenus Rubus, originating from 65 localities in the Czech Republic (Bohemia and Moravia). The species studied include two diploids, one triploid, sixteen tetraploids and one pentaploid. New reports are given for the following seven tetraploid species (2n = 28): R. tabanimontanus Figert, R. salisburgensis Caflisch, R. koehleri Weihe, R. hadracanthos G. Braun, R. franconicus H. E. Weber, R. wessbergii Pedersen et Walsemann and R. mollis J. Presl et C. Presl. A new pentaploid cytotype (2n = 35), different from the tetraploid reported previously in Poland (2n = 28), was found in R. dollnensis Spribille. Brief data on the geographical distribution of the species studied are given; R. wessbergii is reported as a new plant for the flora of the Czech Republic.