| During the summer of 1987 and 1988 twelve Iris lacustris populations in Northern Michigan were studied. Breeding experiments supported Planisek's (1983) assertion that the I. lacustris breeding system is pollinator limited. Insects observed visiting flowers included Syrphid flies, Bombyliid flies, and a small bee. Once established on a site, vegetative propagation is the dominant mode of reproduction in I. lacustris. Transplanted clumps were more successful when transplanted during the early part of the season. Mortality was observed in most populations during the 1988 summer drought. I. lacustris grew under a wide range of ecological conditions and associated with a wide variety of vegetation. Bloom and fruit production, however, was higher in sites with higher light levels and thinner soils. Shoreline disturbance is important in maintaining suitable open habitat for I. lacustris and may partially explain the species' predominantly lake shore distribution. |
