2.2. Pollen limitation
Supplemental hand-pollination was applied on randomly selected individuals (20-30 per species) with at least two open flowers in similar phenological phases. One flower was supplemented by conspecific pollen from plants minimally two meters apart to reduce the genetic closeness and the second was left to natural pollination as a control. Both hand-pollinated and control flowers were marked by coloured cotton yarn loosely knotted under the flowers. In species producing just a single flower (Anemone nemorosa ) or compact inflorescences (Bistorta major ) on a single shoot, we applied the treatments on two neighbouring individuals. In Asteraceae species (Crepis paludosa and Tephroseris crispa ) the treatments were applied on two whole capitula, and in Apiaceae species with compound umbels (Aegopodium podagraria and Chaerophyllum aromaticum ) the treatments were applied on two umbellets from two different umbels. All species with flowers in compact and sequentially opening inflorescences (i.e. Aegopodium podagraria , Bistorta major ,Chaerophyllum aromaticum , Crepis paludosa andTephroseris crispa ) were hand-pollinated repeatedly for several consecutive days throughout the whole flowering period. After the marked flowers wilted, their maturing ovaries were enclosed in fine nylon mesh bags to avoid any seed loss. We counted all viable seeds from the collected flowers or inflorescences and measured mean weight per seed. Because Dactylorhiza majalis produced numerous very small seeds, we used the capsule weight as a proxy for the number of developed seeds.