Breeding system and pollination of selected plants endemic to Juan Fernandez Islands

We conducted field studies on the Juan Fernandez Islands flora on the breed ing system of 25 endemic species from 17 families. We recorded data on flow er features, pollen and ovule number, pollen/ovule ratio, pollen size, self -compatibility, floral visitors, and pollination. Flowers are mostly hermap hrodite, inconspicuous, small, and green. Six species are dioecious. Over 8 06 of the cosexual species are self compatible. However, many species are d ichogamous (mostly protandrous); thus, even the self-compatible species may require pollen transfer. Selfing through geitonogamy seems to be the most common system, and several species express mixed breeding systems. Floral v isitors are uncommon to rare, except for two hummingbird species (one nativ e and one endemic) that visit five species we studied. In more than 300 h o f observation of flowers over three field seasons, we detected only 23 nati ve insect visits representing ten species (Diptera, Lepidoptera, and Coleop tera). One species each of an introduced ant and an introduced bee were als o observed on some flowers, all near the single human settlement of San Jua n Bautista. Wind directly moving pollen, or indirectly via shaking the flow ers. is the most important pollen distribution mechanism. The majority of t he wind-pollinated species bear some typical anemophilous features, but als o others not characteristic of wind pollination, that presumably represent the condition of their biotically pollinated ancestors. Floral features oft en reflect ancestral reproductive systems, so floral biology studies of oce anic islands in particular must be done with cognizance of presumed ancestr al forms, because the observed characters can be misleading.