Floral traits and reproduction of Avicennia schaueriana Moldenke (Acanthaceae): a generalist pollination system in the Lamiales

Pollination systems may vary in their degree of specialization from generalist to specialist and this is associated with the frequency and efficiency of pollinators. Self-compatibility and a generalist pollination system appear to be adaptations that enhance the ability for colonizing new areas, which is typical of mangrove species. Avicennia schaueriana is a western mangrove species included in Acanthaceae, Lamiales, an order known to have specialized pollination. We aimed to describe the floral morphology and analyze the pollination and reproductive systems of A. schaueriana in a mangrove area on the northern coast of the state of Pernambuco, Brazil, to analyze the possible adaptations of this species to the environment. Avicennia schaueriana is self-compatible; however, pollination activity is essential because there is no spontaneous formation of fruit. Reproductive efficacy was high, indicating pollinator efficiency. Some floral attributes of A. schaueriana suggest specialization; however, the broad spectrum of pollinators observed suggests that it has a generalist pollination system. The way in which pollinators interact with flowers and the environmental conditions may have exerted a selective force on the floral attributes of A. schaueriana, characterizing an adaptive generalized pollination system, which is somewhat specialized.