CHROMOSOME-NUMBERS IN SELECTED HIERACIUM SPECIES IN THE KRKONOSE MTS (THE WEST SUDETEN)

Chromosome numbers are given of 15 species of the genus Hieracium L. s str., representing seven species groups (in the sense of Flora Europa ea, roughly corresponding to Zahn's ''species principales'') from the Krkonose Mts., N. Bohemia and SW Poland. For the first time, chromosom e numbers are reported for H. melanocephalum TAUSCH (2n=27), H. tubulo sum TAUSCH (2n=36), H. schustleri ZLATNIK (2n=36), H. fritzei F. SCHUL TZ (2n=27), H. rohlenae ZLATNIK (2n=27), H. nigrescens WILLD (2n=36), H. decipiens TAUSCH (2n=36), H. atrellum JUXIP in SCHISCHKIN et BOBROV (2n=27), H. subnigrescens (FRIES ex NORRLIN) DAHLST. (2n=36), H. sude ticum STERNBERG (2n=36), H. pedunculare TAUSCH (2n=36), H. glandulosod entatum UECHTR. (2n=36), H. wimmeri UECHTR. (2n=27). In Hieracium alpi num L. s. str. the number 2n=27 has been confirmed. The results show a high proportion of tetraploid taxa; no diploids have been found.