Pollen and Seed Morphology as Taxonomic Markers in Verbascum Taxa Based on Herbarium Specimens of MARIUM

Abstract

Herbaria are vital resources of biodiversity education and conservation. They contain significant dried collections and botanical data of plant species that are useful for taxonomy, systematics, and plant-based applied research applications. Verbascum L. is the largest genus within the Scrophulariaceae family globally. However, the high morphological diversity within the genus poses significant challenges for accurate species delimitation. This study investigated the pollen and seed morphology of seven distinct Verbascum groups (comprising 10 taxa, including three endemics) from southeastern Anatolia using scanning electron microscopy (SEM). SEM analyses revealed that all examined taxa possessed tricolporate pollen apertures, with pollen shapes varying between prolate spheroidal and oblate spheroidal. Seeds exhibited a light brown to dark brown color, with a prismatic oblong shape and alveolate surface. The seed coat ornamentation consisted of irregular polygonal cells, densely covered with distinct vesicles. Findings demonstrate significant morphological distinctions in both pollen and seed characteristics, suggesting their utility in taxonomic discrimination within Verbascum groups. Notably, the detailed micromorphology revealed by SEM proved to be particularly valuable for classifying these taxa. These results contribute the understanding of the taxonomic diversity within Verbascum and highlight the crucial role of SEM in uncovering microstructural details for accurate species identification.