Pollen morphology and staminal structure in Salvia and Zhumeria (Lamiaceae)

Pollen of 23 Iranian species of Salvia and Zhumeria were studied using scanning electron microscopy and light microscopy. The staminal structure and floral morphology were examined and compared with palynological data. Pollen in all examined species is hexacolpate isopolar, oblate spheroidal (P/E=0.88-0.99 μm),suboblate (P/E=0.75-0.87 μm) or prolate spherioidal (P/E=1.01-1.02 μm). In polar view two of the mesocolpia are larger than the remaining four. Exine has different ornamentations in apocolpium and mesocolpium. Exine is bireticulate or reticulate perforate. With a few exceptions, three different pollen types could be recognized in Salvia which corresponds with the following three different stamen types: Type I includes species with lower fertile thecae. Pollen exine of this type is bireticulate, lumen with equal size perforations. Type II includes species with sterile dolabriform lower thecae usually connected to each other. Pollen exine of this type is bireticulate, lumen with one or two prominently large perforations. Type III includes species with completely aborted lower thecae. Pollen exine of this type is reticulate perforate, lumen with equal size perforations. In Zhumeria majdae pollen is hexacolpate with two larger mesocolpia, exine is bireticulate, lumen with equal size perforations. Pollen shape and exine ornamentation in Zhumeria is similar to Salvia Type I.