Principal Component Analysis graph. A Scatterplot displaying projections in a multidimensional space of the pollen grain characters: Apocolpium (A), Mesocolpium (M), Equatorial diameter in polar view (EDP) Exine length (EL), Polar Area Index (PAI), Equatorial diameter (ED), Polar axis (PA), Shape class (PE), Spinule length (SL), Spinule base (SB), Perforation diameter (PD). PC1 explains 44% of the variance and PC2 explains 18.4% of the variance B Sorting of the 27 species of tribe Hylocereeae, in relation to the morphometric variables of pollen grains.