The tribe Paullinieae is distinguished by a monoecious reproductive system; it exhibits two floral morphs, namely staminate flowers, with gynoecium reduced to a pistillode, and morphologically hermaphrodite but functionally pistillate flowers. The aim of this study was to analyze the development of sporogenesis and gametogenesis in flowers of Thinouia mucronata Radlk. (subtribe Thinouiinae) and Serjania meridionalis Cambess. (subtribe Paulliniinae) and to elucidate the moment when pollen grains of pistillate flowers and the ovule of staminate ones stopped their development. Light and scanning electron microscopy was applied using standard techniques. In T. mucronata flowers are actinomorphic; the pistillate ones have anatropous, pseudocrassinucellate ovules, without hypostase and with placental obturator, and stamens with indehiscent anthers and well-developed pollen grains that remain inside the pollen sac at the end of anthesis. Serjania meridionalis has zygomorphic flowers, the pistillate ones have campylotropous, crassinucellate ovules, with presence of hypostase, and funicular obturator, and stamens with indehiscent anthers collapsed at the end of anthesis, showing remnants of aborted sporogenous tissue in each pollen sac. Both species share the anatomy of the anther wall; microsporocytes form tetrahedral or decussate tetrads; monads are bicellular; the pistillode has abortive megaspore; gynoecium with bithegmic ovules and Polygonum-type megagametophyte. One difference in antheral wall ontogeny between species was that T. mucronata displayed the dicotyledoneus type development, whereas S. meridionalis exhibited the basic type. These embryological characters clearly support the basal position of Thinouia in the tribe recently validated from molecular phylogeny studies and supported by the present morphological data.

Paullinieae 部落的特点是雌雄同株的生殖系统。它表现出两种花的形态，即雄蕊花，雌蕊减少为雌蕊，以及形态上雌雄同体但功能上雌蕊花。本研究的目的是分析Thinouia mucronata Radlk花中孢子发生和配子发生的发展。（亚部落 Thinouiinae）和Serjania meridionalis Cambess。（亚部落 Paulliniinae）并阐明雌花的花粉粒和雄蕊花的胚珠停止发育的那一刻。使用标准技术应用光学和扫描电子显微镜。在T. mucronata花是辐射对称的；雌蕊具有倒生的假胞胎胚珠，没有胚芽和胎盘闭孔，雄蕊具有不裂的花药和发育良好的花粉粒，在花期结束时留在花粉囊内。小刺槐有左右对称的花，雌蕊的有弯曲的、近核的胚珠，有胚轴和索状闭孔，花药末期有不裂花药的雄蕊倒塌，在每个花粉囊中显示出败育的孢子组织的残余物。两个物种共享花药壁的解剖结构；小孢子细胞形成四面体或交叉四分体；单子是双细胞的；雌蕊有不育的大孢子；雌蕊具双生胚珠和何首乌型巨配子体。物种间花药壁个体发育的一个差异是T. mucronata显示双子叶植物类型发育，而S. meridionalis显示基本类型。这些胚胎学特征清楚地支持了Thinouia的基础位置 在该部落中，最近通过分子系统发育研究进行了验证，并得到了现有形态学数据的支持。