@article {4048, title = {Relationships within the Araceae: comparison of morphological patterns with molecular phylogenies}, year = {2011}, abstract = {

\• Premise of the study: The fi rst family-wide molecular phylogeny of the Araceae, a family of about 3800 published species in 120 genera, became available in 1995, followed by a cladistic analysis of morpho-anatomical data in 1997. The most recent and comprehensive family-wide molecular phylogeny was published in 2008 and included species from 102 genera. We reanalyzed the molecular data with a more complete genus sampling and compared the resulting phylogeny with morphological and anatomical data, with a view to contributing to a new formal classifi cation of the Araceae.
\• Methods: We analyzed 113 aroid genera and 4494 aligned nucleotides that resulted from adding 11 genera to the 2008 molecular matrix. We also analyzed 81 morphological characters in the context of the molecular phylogeny, using an extended version of the 1997 morpho-anatomical data set.
\• Key results: The resulting maximum-likelihood phylogeny is well resolved and supported, and most of the 44 larger clades also have morphological or anatomical synapomorphies as well as ecological or geographic cohesion. Of the 44 clades, 16 are here newly circumscribed and informally named. However, some relationships remain poorly supported within the Aroideae subfamily. The most problematic placement is Calla within Aroideae, which confl icts with the distribution of morphological, anatomical, and palynological character states.
\• Conclusions: The comparison of the molecular analysis with morphological and anatomical data presented here represents an important basis for a new formal classifi cation for the Araceae and for the understanding of the evolution of this ancient family, a monocot group known in the fossil record from the early Cretaceous.

}, keywords = {Araceae, Calla, character evolution, classification, Lemnoideae, molecular phylogeny, phenotypic characterization}, doi = {doi:10.3732/ajb.1000158}, author = {Cusimano, N. and Bogner, J. and Mayo, S.J. and Boyce, P.C. and Wong, S.Y. and Hesse, M. and Hetterscheid, W.L.A. and Keating, R.C. and French, J.C.} } @article {1218, title = {Pollen walls of Araceae, with special reference to their fossilization potential}, journal = {Grana}, volume = {38}, year = {1999}, pages = {203-209}, abstract = {Araceae, 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{\textquoteright}{\textquoteright} 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.}, keywords = {fossils}, issn = {0017-3134}, author = {Hesse, M. and Weber, M. and Halbritter, H.-M.} }