Taxonomic significance of stamens and pollen morphology of some selected taxa of Primulaceae in Egypt

Abstract

Abstract The circumscription study of Primulaceae is still uncertain and remains controversial. Stamens and pollen grains morphological characters of five species and one variety representing five genera viz.,Anagallis, Lysimachia, Coris, Primula and Samolus of Primulaceae in Egypt have been studied using LM and SEM. The specific target of the present study is to evaluate the taxonomic value of the macro and micromorphological characters of stamens and pollen grains in order to distinguish between the studied species. The obtained results showed remarkable variations in anther shape, anther dehiscence, filament attachment and presence of trichomes on the anther filament. Pollen grains are radially symmetrical, isopolar, spheroidal-subprolate to prolate, with amb angulaperturate or fossaperturate and tricolpate or tricolporate. Tectum is microreticulate, reticulate with perforated lumine and clavate exine ornamentation. Out of the studied taxa Coris monspeliensis is distinguished by the presence of prominent margo, reticulate exine ornamentation, minute luminal perforations decreasing towards the colpi, orbicular anther shape, latrorse dehiscence of anthers with short longitudinal slit and presence of glandular diseriate trichomes at the base of the filaments. Clavate exine ornamentation as well as lanceolate anther shape, extrorse dehiscence and short filament can distinguished Samolus valerandi from the remaining studied taxa. An artificial key for the studied species was constructed based on stamens and pollen morphological criteria is provided.