New data on pollination of Iris sibirica L. (Iridaceae)

The flowering period in the population of Iris sibirica in Drogobych district of Lviv region lasts for about 4 weeks, flowering of a five-flowered generative shoot – 10–12 days, flowering of a flower – about 32 hours. The main pollinators of Iris sibirica are Hymenoptera Apis mellifera Linnaeus and Bombus terrestris Linnaeus, and also Coleoptra Variimorda villosa Schrank, Phyllopertha horticola Linnaeus, Lasius niger Linnaeus, Aromia moschata Linnaeus. Protandry has no significant role in the pollination system of Iris sibirica because anther opening proceeds in the closed meranthiun where deposition of pollen on the insect is not possible. Each of three flower meranthium is only once visited by insect. In the studied isolated locality, the mostly geitonogenous pollination inside the individual or clone, as also xenogenous pollination inside the locality, are realized. The male and female reproductive success is higher in the first flower comparing to the fifth flower of the generative shoot, as also P/O index (515 to 338) is. According to the value of P/O index, Iris sibirica is recognized as facultative xenogamous species