Thismia is characterized by an exceptionally complicated floral morphology that is currently not understood properly. In the taxonomic literature, descriptive rather than morphological terms are often applied to parts of the flower in Thismia, relating to the general appearance of the floral organs instead of their precise homologies. Precise understanding of the floral structure is complicated by the rarity of Thismia spp. and the paucity of appropriate material. Here we provide a comprehensive study of reproductive organs of three Thismia spp. (T. annamensis, T. javanica and T. mucronata) including the first investigation of inflorescence architecture and early floral development in Thismiaceae. We found a hitherto unknown diversity of the reproductive shoots in the genus, manifested in the number of floral prophylls (two or three, in contrast to a single prophyll in the vast majority of monocots) and in the branching plane resulting in two distinct inflorescence types, a drepanium and a bostryx. We report the non-acropetal sequence of initiation of floral whorls (with stamens being the last elements to initiate), never previously described in monocots, and the gynoecium composed of completely plicate carpels, also a rare feature for monocots. Floral vasculature is relatively uniform in Thismia, but significant interspecific differences are found in tepal innervation, including the number of tepal traces; some of these differences are not immediately related to the external tepal morphology. We argue that the annulus, which acts as a roof of the hypanthium, possesses an androecium nature and represents congenitally fused bases of stamen filaments. We describe the stamens as laminar structures, which are also shortly tubular in the distal part of the supraconnective with the adaxial tubular side forming a skirt-like appendage. Finally, the placentas, which are column-like when mature, are initially parietal, becoming secondarily similar to free-central placentas through schizogenous separation from the ovary wall.

中文翻译：

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Thismia（Thismiaceae：Dioscoreales）中的花卉结构：来自解剖，脉管系统和发育的新见解

该虫的特征是异常复杂的花卉形态，目前尚无法正确理解。在分类学文献中，描述性而非形态术语通常用于“ Thismia ”中花朵的一部分，与花朵器官的总体外观有关，而不是与它们的精确同源性有关。Thismia spp的稀有性使对花艺结构的精确理解变得复杂。以及缺乏适当的材料。在这里，我们提供了三个Thismia spp生殖器官的全面研究。（T. annamensis，T. javanica和T. mucronata），包括对菊科的花序结构和早期花卉发育的首次调查。我们发现该属生殖芽的一种迄今未知的多样性，表现为花肉的数量（两个或三个，与绝大多数单子叶植物中的单个肉相比）和分支平面导致两种不同的花序类型，a和dr。我们报告了非轮生的花序轮生的启动过程（雄蕊是最后一个要启动的元素），这在单子叶植物中是从未有过的描述，而由完全重复的心皮组成的妇科，也是单子叶植物的罕见特征。在Thismia中，花的脉管系统相对均匀，但在花被神经支配中发现明显的种间差异，包括花被痕迹的数量；这些差异中的一些与外部花被形态没有直接关系。我们认为，作为玻璃托的屋顶的环具有雄蕊的性质，并代表雄蕊丝的先天融合基部。我们将雄蕊描述为层状结构，其在上连接的远侧部分中也呈短管形，与近端管状侧形成裙状的附属物。最后，成熟时呈柱状的胎盘最初是顶叶的，其次是通过与子房壁发生分裂分离而变得与自由中心胎盘相似。