In the subfamily Bromelioideae, the so-called Nidularioid genera share some morphological features, the most notable of which is the occurrence of congested inflorescences that accumulate different amounts of water. This study aims to describe and compare the inflorescence morphology in six Nidularioid genera and to estimate the “tank space” for water in each inflorescence. Inflorescences at different developmental stages were analyzed using light microscopy and described using a typology-based comparative approach. X-ray microtomography was used to obtain sections of young inflorescences, from which 3-dimensional images were built for exploring structural issues and estimating water impounding capacity. Inflorescences are simple racemes in N. johannis and heterothetic compound racemes in the other species. No adaxial prophylls were observed among Nidularioid genera, neither in floral axes nor in the inflorescence branches. The flowers are spirally arranged along the florescence axis although the polystichous condition is obscured by the dorsiventral compression of florescences. The development of Nidularioid compound inflorescences follows a bidirectional pattern since flower primordia differentiate acropetally and paraclade primordia develop basipetally. Bracts are used for water storage in species with a long scape, where such bracts are large and cover the entire paraclades. In species with a short floral scape, inflorescences remain submerged inside the vegetative phytotelmata, allowing these inflorescences to be always in contact with water. Despite the actual branching pattern is obscured because the inflorescence branches are closely condensed in the axils of water impounding bracts, all Nidularioid inflorescences constitute polytelic systems that follow the general pattern of Bromeliaceae. Although all Nidularioid inflorescences are associated with structures for water retention, they seem not to be synapomorphic. Thus, hypotheses of primary homology suggested by both the typological analysis of inflorescences and the survey of water-impounding structures are consistent with the non-monophyletic condition of the Nidularioid genera.

在 Bromelioideae 亚科中，所谓的 Nidularioid 属具有一些形态特征，其中最显着的是出现聚集不同量水的密集花序。本研究旨在描述和比较六个 Nidularioid 属的花序形态，并估计每个花序中水的“水箱空间”。使用光学显微镜分析不同发育阶段的花序，并使用基于类型学的比较方法进行描述。X 射线显微断层扫描用于获取幼花序的切片，从中构建 3 维图像以探索结构问题和估计蓄水能力。约翰尼斯猪笼草的花序是简单的总状花序和其他物种中的杂合复合外消旋体。在 Nidularioid 属中没有观察到正面前叶，无论是在花轴还是在花序枝中。花沿着花序轴呈螺旋状排列，尽管多刺条件被花序的背腹压缩所掩盖。Nidularioid 复合花序的发育遵循双向模式，因为花原基向顶叶分化，而副进化枝原基向基叶发育。苞片用于具有长花序的物种的蓄水，这些苞片大并且覆盖整个副进化枝。在花序较短的物种中，花序仍然浸没在植物性植物纤维内，使这些花序始终与水接触。尽管由于花序分枝在蓄水苞片的腋中紧密浓缩，因此实际的分枝模式被掩盖了，但所有 Nidularioid 花序都构成了遵循凤梨科一般模式的多叶系统。尽管所有 Nidularioid 花序都与保水结构有关，但它们似乎不是突触的。因此，花序的类型分析和蓄水结构的调查所提出的主要同源性假设与 Nidularioid 属的非单系条件一致。尽管所有 Nidularioid 花序都与保水结构有关，但它们似乎不是突触的。因此，花序的类型分析和蓄水结构的调查所提出的主要同源性假设与 Nidularioid 属的非单系条件一致。尽管所有 Nidularioid 花序都与保水结构有关，但它们似乎不是突触的。因此，花序的类型分析和蓄水结构的调查所提出的主要同源性假设与 Nidularioid 属的非单系条件一致。