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/4301912nas a2200181   4500008004100000022001400041245009700055210006900152300001200221490000800233520135200241653001201593100001801605700002001623700001501643700002401658856004801682       2007                        eng d  a1612-412X00aNew fossil leaves of Araceae from the Late Cretaceous and Paleogene of western North America0 aNew fossil leaves of Araceae from the Late Cretaceous and Paleog  a133-1470 vA473 aThe fossil record of Araceae is expanded by three new leaf species from the Upper Cretaceous and Paleogene of North America: 1) Orontium wolfei BOGNER, K. JOHNSON, KVA{\v C}EK & UPCHURCH sp. nov. (Lower–Middle Eocene, northern Washington and southern British Columbia); 2) Orontium mackii BOGNER, K. JOHNSON, KVA{\v C}EK & UPCHURCH sp. nov. (Maastrichtian, New Mexico); and 3) Symplocarpus hoffmaniae BOGNER, K. JOHNSON, KVA{\v C}EK & UPCHURCH sp. nov. (uppermost Maastrichtian of North Dakota and lowermost Paleocene of Colorado). A fourth representative of Orontioideae, Lysichiton austriacus (J. KVA{\v C}EK & A.B. HERMAN ) BOGNER, K. JOHNSON, KVA{\v C}EK & UPCHURCH comb. nov., is based on a leaf fossil described from the lower Campanian of Grünbach, Austria, central Europe, and its name is re-combined herein from Araciphyllites. All species can be assigned to Araceae, subfamily Orontioideae, based on their distinctive patterns of venation, which are directly comparable to those of extant genera. This indicates that the Orontioideae originated sometime during the Cretaceous, and that the lineages related to extant genera were present by the Campanian-Maastrichtian. Climatic analysis of associated leaf assemblages indicates that the thermal tolerances of fossil Orontioideae mostly fall within the range of living representatives.10afossils1 aBogner, Josef1 aJohnson, K., R.1 aKvacek, Z.1 aJr., G., R. Upchurc  uhttps://cate-araceae.myspecies.info/node/20