Pollen Micromorphology of 12 Taxa of Delphinium in Türkiye and Their Taxonomic Importance

Pollen micromorphology of 12 taxa belonging to genus Delphinium L. (Ranunculaceae) species was investigated by light microscopy and scanning electron microscopy. Pollen slides were prepared using the Wodehouse technique. Measurements were based on 30 or more pollen grains per specimen. For scanning electron microscopy studies, dried pollen grains were transferred to aluminium stubs and coated with gold for 3 min in a sputter-coater. The pollen grains of Delphinium taxa are radially symmetric and isopolar. The pollen grains of the taxa are prolate–spheroidal, subprolate with the polar axes 24.51–36.24 μm and the equatorial diameter 22.13–30.43 μm. The pollen grains are tricolpate rarely tetracolpate (D. thrikeana). Colpi were usually long and narrow (Clg: 18.46–28.73 μm; Clt: 5.17–9.31 μm) and granulate. Pollen grains show microechinate, microechinate-perforate, microechinate-verrucate. Exine is subtectate and has a thickness of 0.99–1.58 μm. Ectexine is thicker than endexine. Intine has a thickness of 0.39–0.69 μm. As result of this study, some pollen characteristic as pollen shape, aperture type, and ornamentations are shown to vary within the genus. Especially, pollen surface ornamentation has systematic value to distinguish taxa from each other. Cluster and principal component analyses supported the separation of taxa into three types. Type 1 and Type 2 differed mainly in pollen size and aperture dimensions, while D. saccatum (Type 3) was characterized by thicker exine and intine layers. Taxa formerly classified under Consolida clustered together as Type 2, indicating consistent morphological differentiation within the genus Delphinium. These statistical results support the taxonomic value of quantitative pollen traits.