Principal Components Analysis graph showing contribution of the thirteen attributes to explain variation in pollen grains of the studied Dahlia and Hidalgoa species. Pa Polar axis, Et Exine thickness, Cl Colpus length, Cw Colpus width, Ol Os length, Ow Os width, Sl Spine length, Swab Spine width at base, Na Number of apertures, Ns Number of spines/100 μm2, Ce Colpus ends, Sb Base of spine, Osl Os lalongate.