Landesmuseum für Kärnten, Botanikzentrum, Prof.-Dr.-Kahler Platz 1, A-9020 Klagenfurt, Austria.
Am J Bot. 2009 Jun;96(6):1055-67. doi: 10.3732/ajb.0800289. Epub 2009 May 7.
Extreme modification and reduction in floral morphology presents an obstacle to determining the evolutionary relationships and homologies of the holoparasites in Balanophoraceae. Developing flowers and inflorescences of two dioecious species, Balanophora papuana and B. elongata, were compared to each other and to the monoecious B. fungosa. Intermingled with flowers in the male inflorescences are bracts (B. elongata) or bract parts (B. papuana). In the latter, early cessation of bract tip growth results in two half-bracts, which become displaced during inflorescence elongation, thus disproving the view that these bract-like structures are axial in nature. Male flower primordia emerge in positions axillary to the dividing bracts, and both arise in a spiral sequence. This pattern is modified in B. papuana by the formation of pseudowhorls of four. In both species, the staminate flowers consist of a generally four-merous perianth and a synandrium of congenitally fused stamens. Male flower and bract ontogeny (but not pollen sacs) conform to patterns seen in other angiosperms. More problematic are the carpellate flowers whose primordia arise in irregular order between club-shaped, radially symmetrical organs called claviform bodies. The interpretation that these bodies are homologous to the peltate bracts of Helosideae appears plausible, but cannot explain their nonspiral initiation and radial symmetry.
极端的花部形态修饰和简化给确定蛇菰科全寄生植物的进化关系和同源性带来了障碍。本文比较了雌雄异株的两种植物，Balanophora papuana 和 B. elongata 的花和花序，以及雌雄同株的 B. fungosa。在雄花序中与花混生的有苞片（B. elongata）或苞片的一部分（B. papuana）。在后一种植物中，苞片先端生长的早期停止导致形成两个半苞片，在花序伸长过程中发生位移，因此证明这些类似苞片的结构不是轴向的观点是错误的。雄花原基在分生的苞片腋部出现，并且都以螺旋状顺序出现。B. papuana 中的这种模式通过形成四个假轮状结构而改变。在这两个物种中，雄花由通常具有四枚花瓣的花被和合生的雄蕊的合蕊柱组成。雄花和苞片的个体发生（但不包括花粉囊）符合在其他被子植物中看到的模式。更成问题的是雌花，其原基以不规则的顺序在棒状、辐射对称的器官（称为棒状体）之间产生。这些器官与旋蒴苣苔科的盾状苞片同源的解释似乎是合理的，但不能解释它们的非螺旋起始和辐射对称。
