Reproductive structures and phylogenetic significance of extant primitive Angiosperms |
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Authors: | Peter K. Endress |
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Affiliation: | (1) Institut für Systematische Botanik der Universität, Zollikerstrasse 107, CH-8008 Zürich, Switzerland |
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Abstract: | A brief survey is presented on fossil reproductive structures of early Angiosperms from the Lower and mid-Cretaceous and at the same time on the reproductive structures of those extant Angiosperms which resemble most closely these fossils and which seem to be especially primitive also on other grounds: a first group (Degeneriaceae, Himantandraceae, Eupomatiaceae, Austrobaileyaceae) possessing relatively complicated and conspicuous flowers with elaborated inner staminodes, a second group (Chloranthaceae, Trimeniaceae, Amborellaceae) possessing small and relatively simple, inconspicuous flowers with peculiar features in the carpels, and a third group (Winteraceae) possessing flowers with unusual variability in organ number and size. The three groups exhibit a certain diversity in pollination biology, although cantharophily seems to prevail, however different the cantharophily character syndromes may be between the groups. In the extant primitiveMagnoliidae variability occurs on other morphological levels than in the higher advanced Angiosperms. This has to be taken into consideration in evaluations of the systematic relationships of the various groups of theMagnoliidae. Presumably often their relationships are closer than it may appear at first sight. This is also true for the three groups here discussed. |
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Keywords: | Primitive Angiosperms early Angiosperm fossils Degeneriaceae Himantandraceae Eupomatiaceae Austrobaileyaceae Chloranthaceae Trimeniaceae Amborellaceae Winteraceae Floral phyllotaxy organ number androecium gynoecium Floral evolution |
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