Pollen morphology of the genus Rubus L. I. introductory studies on the european representatives of the subgenus Rubus L.

Abstract

The results of pollen morphology studies of 9 European Rubus species are presented in this paper (R. apricus, R. armeniacus, R. divaricatus, R. fabrimontanus, R. gracilis, R. hirtus, R. laciniatus, R. nessensis and R. pedemontanus). The examination is made by SEM observation for first time and also by LM. All examined pollen grains are small, isopolar and tricolporate. All grains, except for R. armeniacus and R. gracilis tend to have very long colpi. Equatorial bridges constricted, make the pores unvisible in most of the species. R. apricus, R. armeniacus, R. gracilis and R. pedemontanus have the equatorial bridges stretched therefore the dark whole was only the trace of existing endoaperture. The sculpture of the grain confirms striate pattern and the orientation of the muri indicates the differences between the species; R. pedemontanus and R. fabrimontanus appear to have long, compact muri, parallelly orientated to the colpus; R. nessensis appears muri meandrically orientated, reminiscent of "finger prints" pattern with distinct thickenings in the place of connection and numerous narrow grooves with perforations. R. hirtus appears to have striate-scabrate sculpture because of granular elements (punctae) dispersed between the muri on all over the grain like the internal part of the exine. Shape and size turned out to be a poor criterion for identifying species.