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.
a b s t r a c tResults of the present study indicate that male cones of Pseudotaxus chienii are representing inflorescences with strongly reduced flowers. The results fit quite well with investigations showing that sporangiophores of Taxus and also of Pseudotaxus comply with reduced flowers. The only difference between male cones in Taxus and Pseudotaxus is the absence of pherophylls in Taxus. Furthermore our results complete a transition series beginning with Cephalotaxus going on to Pseudotaxus and ending with Taxus and Torreya. In this progression Pseudotaxus can be regarded as an intermediate link between the inflorescences of Cephalotaxus and the simple, unbranched cones of Taxus. The entire transition series shows that sporophyll-like sporangiophores can be derived by reduction of lateral cones. There is however no sign that a similar process has occurred in other conifer groups. (T. Stützel). 1 We avoid using the term "sporophyll" or "microsporophyll" for the sporangia bearing structure. Otherwise we would have introduced a priory a homology with the terminology applied, which we want to analyze in our comparative study. 0367-2530/$ -see front matter
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