New York Botanical Garden, Bronx, New York 10458 USA.
Am J Bot. 2003 Nov;90(11):1548-59. doi: 10.3732/ajb.90.11.1548.
A conspicuous feature of Vochysiaceae flowers is their single fertile stamen. In some genera, the stamen is in front of a petal, whereas in others it is in front of a sepal. This difference has been attributed to two independent reductions, which implies the stamen is not homologous across the family. The observation that genera with an antesepalous stamen have only one petal, whereas those with an antepetalous stamen have three or five petals, led us to the hypothesis that in all genera the stamen arises in an antepetalous position, but that it is displaced during development in single-petaled taxa. We examined developing buds of five genera using scanning electron microscopy and serial sectioning and conclude that the stamen in all genera is fundamentally antepetalous. The stamen is not displaced. The petal, however, appears to be displaced in some genera. Further, the position of the fertile stamen in Erisma has been misinterpreted. We discuss the evolution of the androecium in this family in a phylogenetic context and consider the significance of symmetry and of loss vs. suppression in the development of Vochysiaceae flowers.
紫葳科花朵的一个显著特征是其单个可育雄蕊。在某些属中，雄蕊位于花瓣前面，而在其他属中则位于萼片前面。这种差异归因于两次独立的退化，这意味着在整个科中，雄蕊不是同源的。观察到具有前萼片雄蕊的属只有一个花瓣，而具有前花瓣雄蕊的属有三个或五个花瓣，这使我们假设在所有属中，雄蕊都在前花瓣的位置出现，但在单瓣类群的发育过程中会发生位移。我们使用扫描电子显微镜和连续切片检查了五个属的发育芽，得出的结论是，所有属的雄蕊本质上都是前花瓣的。雄蕊没有发生位移。然而，在某些属中，花瓣似乎发生了位移。此外，Erisma 中可育雄蕊的位置被误解了。我们在系统发育背景下讨论了该科雄蕊的进化，并考虑了对称性以及 Vochysiaceae 花朵发育过程中缺失与抑制的意义。
