Pollen morphology in Saxifraga （Saxifragaceae） from NyAlesund, Svalbard, Arctic, and its taxonomic significance

Pollen morphology of eight species of Saxifraga,i.e.S.cespitosa,S.oppositifolia,S.cernua,S.nivalis,S.aizoides,S.rivularis,S.hieraciifolia,and S.hirculus,collected from Ny-Alesund,Svalbard,Arctic was examined using light and scanning electron microscopy.Pollen grains of Saxifraga species are subprolate or prolate,3-colpate,15.4–44.4μm in the polar axis,11.4–34.6μm in the equatorial axis,and show a P/E ratio 1.19–1.40.On the basis of exine ornamentation,four pollen types,viz.,the S.oppositifolia type(striate without scabrae on the muri),S.cernua type(striate with scabrae on the muri),S.nivalis type(microreticulate and operculum absent),and S.cespitosa type(microechinate and operculum present),were recognized.Hierarchical cluster analysis of the pollen morphological characters indicated that pollen morphology supports the infrageneric classification of the genus Saxifraga.