Pollen morphology of Polygonatae and its systematic significance

The pollen morphology of 54 species and one variety of seven genera in Polygonatae including <i>Clintonia</i>, <i>Disporopsis</i>, <i>Disporum</i>, <i>Maianthemum</i>, <i>Polygonatum</i>, <i>Smilacina</i> and <i>Streptopus</i> was observed and studied in detail; of these, nine species were reported for the first time. Our results showed that the surface ornamentation of pollen grains of the studied materials could be divided into seven types, namely gemmate, granulate-foveolate, perforate, reticulate, rugulate, rugulate-perforate and verrucate. In line with previous studies, we believe that (i) <i>Smilacina ginfushanicum</i> should be classified into the genus <i>Heteropolygonatum</i> rather than the genus <i>Smilacina</i>; (ii) <i>Polygonatum</i> should be divided into section <i>Polygonatum</i> and section <i>Verticillata</i>; (iii) <i>Smilacina</i> and <i>Maianthemum</i> should be combined as one genus, i.e. <i>Maianthemum sensu lato</i>; and (iv) <i>Clintonia</i>, <i>Disporum</i> and <i>Streptopus</i> should be separated from the tribe Polygonatae.