| The other parts constituting the wall of the grain are an inner layer, the intine, and an outer layer, the exine. |
| For example, the top surface is analyzed to understand the ornamentation while the central images help to identify the cytoplasm or the exine thickness. |
| The two morphs of both species produce equivalent numbers of pollen grains, but the grains differ with respect to exine sculpturing and size. |
| Acetolysis and treatment with NaOH are known to dissolve the exine of Xyridaceae pollen, thus only untreated grains were examined. |
| Recent palynological research has revealed diverse exine ornamentation in Rheum, but the variations in ornamentation are not consistent with the morphological classification. |
| Clypeate grains are either functionally omniaperturate and have a thin exine and uniformly thickened intine or are porate with localized thickenings of intine. |
