Male Cones in Taxaceae s. l. - an Example of Wettstein's Pseudanthium Concept

Abstract: Male cones of Taxus baccata L. and Torreya californica Torr. are mostly regarded as simple strobili ("flowers"). In the past some authors assumed that every single "sporangiophore" of Taxus baccata represents a whole "flower". The male cone of Taxus would then represent a compound strobilus ("inflorescence"). A cone of Cephalotaxus harringtonia (Knight ex J. Forbes) K. Koch and Cephalotaxus fortunei Hook. can easily be recognized as a compound strobilus composed of several simple strobili.
Our developmental studies by SEM give clues to the assumption that a simple male strobilus in Cephalotaxus is not homologous to the male strobili in Taxus and Torreya. Developmental, morphological and anatomical studies suggest that the simple strobili of Taxus and Torreya are derived from the compound strobili in Cephalotaxus by a transformation of the simple strobili into single sporangiophores. With respect to morphology, the male cones in Taxus and Torreya are simple strobili, but comparative developmental studies show that they are derived from compound strobili in a process similar to Wettstein's pseudanthium hypothesis. In the light of our studies, it is not unlikely that the male cones in Pinaceae also represent transformed compound strobili.