01671nas a2200169   4500008004100000022001400041245008500055210006900140300001200209490000700221520116300228653001201391100001401403700001401417700002201431856004801453       1999                        eng d  a0017-313400aPollen walls of Araceae, with special reference to their fossilization potential0 aPollen walls of Araceae with special reference to their fossiliz  a203-2090 v383 aAraceae, a basal monocot family, has a very poor fossil record, especially with regard to pollen grains. An ultrastructural study of Araceae pollen walls was undertaken to answer the questions: which pollen is resistant to decay and will appear in the fossil record? and which pollen has a smaller fossilization potential and why? The wall strata of Araceae pollen differ in morphology and chemical composition. Only a minority of all Araceae pollen grains has the "conventional’’ type of exine architecture consisting of an acetolysis-resistant ektexine upon a generally thin, but ratherspongy endexine. Pollen grains with this type of exine have a high fossilization potential and should be found unmodified in the fossil record. In contrast, the majority of Araceae pollen has a strikingly different, newly discovered exine architecture: a thick, spongy, acetolysis-resistant endexine is covered by an outer stratum, which either may or may not be resistant to acetolysis. We conclude from these features that the potential for fossilization is greatly reduced. Moreover, pollen remnants, if at all preserved, should be found in a highly modifed form.10afossils1 aHesse, M.1 aWeber, M.1 aHalbritter, H.-M.  uhttps://cate-araceae.myspecies.info/node/43