Pollen morphological study of some species of the genus Rubus L. (Rosaceae) of the flora of Armenia

Pollen morphology of 10 Armenian species of the genus Rubus L. was studied using both light microscopy (LM) and scanning electron microscopy (SEM), including the species R. candicans, R. cartalinicus and R. takhtadjanii investigated for the first time. The data received revealed the significant palynomorphological uniformity in the aperture type: mainly 3-zonocolporate, geniculate, occasionally 4-zonocolporate one. In some 4-zonocolporate pollen grains of the species R. armeniacus, additional slit-like or colpus-like areas were also noted at one or both poles. Exine ornamentation was predominantly finely striate-perforate (SEM), sometimes in combination with finely striate-microreticulate one (R. armeniacus and R. caesius). Pollen grains were small, sometimes of medium size also. The smallest pollen grains (according to polar axis length) were observed in the species R. takhtadjanii (on average 14.2 mu m), and the largest ones in R. caucasicus (on average 26.3 mu m). Our data support the previously held view that pollen grain morphology within the genus Rubus can only be used as an auxiliary feature for the diagnosis of individual species.