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

Chromosome numbers are given for 26 species representing predominantly the subgenus Rubus (23 species) as well as the subgenera Chamaerubus (1 species) and Idaeobatus (2 species). The plants studied were collected from 84 localities in the Czech Republic (Bohemia and Moravia). Five ploidy levels were found including diploids (two species), triploids (five species), tetraploids (fifteen species), pentaploids (three species) and one octoploid: both diploids and the single octoploid do not belong to the subgenus Rubus. The chromosome numbers in the following thirteen species of the subgenus Rubus are reported here for the first time: R. graecensis Maurer, R. henrici-egonis Holub, R. austromoravicus Holub, R. crispomarginatus Holub (all triploid species, 2n = 21); R. micans Godron,R. caflischii Focke, R. chaerophyllus Sag. et W. Schultze, R. vratnensis Holub, R. centrobohemicus Holub, R. epipsilos Focke, R. bavaricus (Focke) Hruby, R. lusaticus Rostock and R. lividus G. Braun (all tetraploid species, 2n = 28). In addition to chromosome numbers, data on the geographical distribution of the species studied are also briefly mentioned. Rubus caflischii is reported here for the first time from the area of the Czech Republic (Český les Mts). Rubus graecensis was found as a new plant for Bohemia. Rubus micans occurs in the Czech Republic separated by a large hiatus of more than 700 km from its distribution in western Europe; it is also recorded as a new plant for the flora of Poland. The species R. caflischii, R. lividus, R. lusaticus and R. micans are known only from one locality each in the Czech Republic. All earlier data on R. grossus H. E. Weber 1989 from the Czech Republic belong to the newly described species R. kuleszae Zielinski 1996. R. crispomarginatus was found also in Germany and Austria as a new plant for the flora of these countries. A description of a new taxon - ser. Idaei Holub - belonging to subgen. Idaeobatus is given.