ABSTRACT:

The pollen aperture of Lasioideae (sensu Mayo et al., 1997) is a sulcus with two unique characters, seen only in ultrathin sections. A continuous ectexine lamella overspans the whole furrow. Below a thick, bilayered endexine is found. Its outer part consists of isolated flakes or discontinuous lamellae, while the inner part is spongy. The endexine flakes are usually absent in the central sulcus area. This unique aperture stratification is restricted to the Lasioideae. It is absent not only in the other Araceae subfamilies (therefore confirming the homogeneity of Lasioideae), but also not found in any other angiosperm pollen. This peculiarity of all Lasioideae may be correlated with the socalled harmomegathic effect, and as a functional benefit a better preservation from dehydration can be assumed.