Abstract: Anaphalis is one of the largest genera of the Asian Gnaphalieae (Asteraceae) and is most diversified on the Qinghai-Tibet Plateau. The chromosome numbers and karyomorphology of six species from seven populations were investigated for the first time for this region. Chromosome numbers have been newly documented for four species: Anaphalis deserti (2n=56=24m+24sm+8st), A. plicata (2n=56=26m+30sm), A. xylorhiza (2n=28=2M+14m+12sm),and A. rhododactyla (2n=56=32m+24sm). Two further counts are in agreement with the previously reported numbers, i.e., Anaphalis royleana (2n=28=4M+6m+18sm) and A. margaritacea (2n=28=12m+16sm). A new polyploid cytotype (2n=56=26m+30sm) was found in the Zougong population of A. margaritacea. Polyploidy is for the first time reported for Anaphalis, with four out of seven counts being tetraploid. Our cytological results suggest that polyploids may have played an important role in the evolution of Anaphalis on the Qinghai-Tibet Plateau.

Key words: Anaphalis DC., Asteraceae, Chromosome number, Gnaphalieae, Polyploidy, Qinghai-Tibet Plateau.