FLOWERING ABUNDANCE AND POLLEN PRODUCTIVITY OF Ligularia clivorum Maxim. AND Ligularia przewalskii Maxim.

Ligularia genus includes species cultivated in house gardens and urban parks as an attractive ornamental plants. During flowering period their flower heads may provide pollen food for pollinators. In the period 2004-2008, the present study investigated the abundance of flowering and pollen production of two Ligularia species as a source of pol- len for insects. Under the conditions of Lublin, the onset of flowering of L. clivorum oc- curs in the second half of July, whereas L. przewalskii starts to bloom already in the last week of June. Depending on species and weather conditions, the period of flowering of L. clivorum lasted 48-67 days, while in the case of L. przewalskii from 29 to 38 days. In both taxa, female ray florets and bisexual disc florets are found in capitulum inflorescen- ces. The weight of pollen produced by 10 L. clivorum flowers was almost twice higher than that in L. przewalskii. Pollen production per unit area for these taxa was 6.92 g·m -2 and 1.53 g·m -2 , respectively.