Lack of correlation between pollen aperture number and environmental factors in pansies (Viola L., sect. Melanium Ging.) - pollen heteromorphism re-examined

The development of different pollen morphs by one specimen - pollen heteromorphism - occurs in ca. one-third species of the genus Viola. Melanium section species (pansies) stand out in producing the widest range of apertures among Viola species. Aperture number decreases with elevation increase, and faster germination of five-aperturate pollen as compared with three-aperturate has previously been postulated. We re-examined pollen heteromorphism in the context of its viability, and made correlations with elevation (>1500 m a.s.l. versus