This study is the first comparison of the morphology of pollen grains in ten cultivars of three species of the Taxus, Torreya nucifera and Cephalotaxus harringtonia var. drupacea genera. The material came from the Botanical Garden of Adam Mickiewicz University in Poznań, Poland. Each measurement sample consisted of 50 pollen grains. In total, 750 pollen grains were analyzed. Light and electron scanning microscopy was used for the morphometric observation and analysis of pollen grains. The pollen grains were inaperturate and classified as small and medium-sized. They were prolate-spheroidal, subprolate to prolate in shape. The surface of the exine was microverrucate-orbiculate, perforate in Cephalotaxus harringtonia var. drupacea, granulate-orbiculate, perforate in all Taxus taxa and granulate-microverrucate-orbiculate, perforate in Torreya. The orbicules were rounded to oval in surface view, and the size was considerably diversified. The pollen features were insufficient to distinguish between individual Taxus members – only groups were identified. The values of the coefficient of variability of three features (LA, SA and LA/SA) were significantly lower than the orbicule diameter. The pollen surface of all Taxus specimens was similar, so it was not a good identification criterion. The pollen grains of the Taxus taxa were smaller and had more orbicules than Cephalotaxus and Torreya. Palynological studies provided taxonomic support for recognition of two different genera of the Cephalotaxaceae and Taxaceae families, which are closely related.
Abstract Pollen grains of Pinus mugo, P. sylvestris and P. ×rhaetica (= P. mugo × P. sylvestris) were examined by light and scanning electron microscopy. The pollen grains were bisaccate and monosulcate. The corpus-saccus attachment was distinct. The pollen corpus exine sculpture was verrucate-rugulate and deeply sculptured. The surface of the tectum was covered with small grana and it was perforate. The saccus sexine ornamentation was reticulate and irregularly perforate. The tectum surface characters in the proximal and distal view of the corpus and saccus were less variable and they did not provide good criteria to identify the species under study. However, some differences were observed in the size of elevation on the corpus between pollen grains of the same species and between the parental species. This study of the pollen grain morphology of the corpus and saccus provided some important new data.