Pollen Morphology of Egyptian Geraniaceae: An Assessment of Taxonomic Value

Pollen morphology of sixteen species including two subspecies and representing four genera: Geranium L., Erodium L., Monsonia L. and Pelargonium L′ Hér. of Geraniaceae in Egypt were investigated by the aid of light and scanning electron microscopy. The study showed that pollen grains were radially symmetrical, isopolar, prolate spheroidal to oblate spheroidal, tricolp (ate) orate. Tectum was generally striate/reticulate, reticulate/gemmate or reticulate. On the basis of pollen morphological characters, principally aperture types and exine sculpture, pollen grains were separated into three types and three subtypes representing different taxonomic categories. A key to the different pollen types and subtypes was provided. The results demonstrated that pollen morphological characters, as pollen shape, size, aperture characters as well as exine sculpture and structure, were taxonomically significant at the generic level and to some extent at the specific level. Moreover, the results confirmed the eurypalynous nature of the family.