Pollen morphology and flower visitors of Leiotulus aureus (Sm.) Pimenov & Ostr. (Apiaceae)

The pollen grains of Leiotulus aureus (syn. Malabaila aurea (Sm.) Boiss.) were examined by light and scanning electron microscopy in order to contribute to the taxonomical and melissopalynological studies of the species. Flower visitors have also been observed and analyzed aiming at clarifying some pollination aspects including the species contribution to the bee pasture. The pollen grains of L. aureus are isopolar, radially symmetrical, medium to large in size, tricolporate and perprolate. They are slightly equatorially constricted with obtuse polar caps and triangular in polar view. The sculpturing pattern is rugulate–microperforate. With regard to flower visitors, the following pollination types occurred: melittophily, myophily and sapromyophily and cantharophily. Some insects attracted by L. aureus cannot be considered pollinators but casual visitors. The flowers were the most frequently visited by honey bees during the midday.