Abstract

Decalobanthus is a genus of woody climbers of Convolvulaceae, recently expanded from a monotypic genus to including 17 species, mainly distributed in Asia and the Pacific. Despite the monophyly and the strong morphological and geographical coherence of the genus, only five of its species have been sampled in a molecular phylogenetic study and their relationships remain poorly understood. As a pillar to further systematic and evolutionary studies of Decalobanthus, this study offers a full characterisation of its pollen variation. To date, only seven of the 17 species have been palynologically documented in the literature (as Merremia s.l.). We here offer new data for seven species, which adding up to the already available data, totals a characterisation of 14 out of the 17 species in the genus. The pollen of Decalobanthus is, in most cases, tricolpate, with one species presenting hexapantocolpate polymorphism, which could suggest di/polyploidy; the presence of a reticulate exine (‘reticulum cristatum’ type) is remarkable, in Convolvulaceae only known otherwise in some species of Cuscuta.

摘要

Decalobanthus是旋花科木本攀缘植物的一个属，最近从单型属扩展到包括 17 种，主要分布在亚洲和太平洋地区。尽管该属具有单系性和强大的形态学和地理一致性，但在分子系统发育研究中仅对其五个物种进行了采样，并且对它们的关系仍然知之甚少。作为进一步系统和进化研究Decalobanthus 的支柱，这项研究提供了其花粉变异的完整特征。迄今为止，文献中仅对 17 个物种中的 7 个物种进行孢粉学记录（如Merremia sl.) 我们在这里提供了七个物种的新数据，这些数据与现有数据相加，总共表征了该属 17 个物种中的 14 个。花粉Decalobanthus是，在大多数情况下，三沟，有一个品种呈现hexapantocolpate多态性，这可能表明DI /多倍体; 网状外壁（'reticulum cristatum'型）的存在是显着的，在旋花科中仅在菟丝子的某些物种中已知。