The first report on nectar release in the Melastomataceae was made by Ule (1896) on Tibouchina, a large genus with over 350 species, most of which are bee-pollinated ( Renner, 1989). However, nectariferous Melastomataceae, which mostly retain poricidal anthers, have evolved other strategies for attracting pollinators. Their poricidal anthers have been seen as a specialization to protect the pollen, ensuring that it is only collected by bees. Pollen of Melastomataceae can be of great ecological importance in the neotropics, where melastome flowers have been shown to be visited by up to 40 % of bee species in a given locality ( Renner, 1989 Harter et al., 2002). Melastomataceae flowers are known for usually providing pollen rewards to their pollinators. Charianthus nectaries were not found, but there is circumstantial evidence that nectar release occurs through the epidermis at the apex of the ovary and the lower portions of the inner wall of the hypanthium. Miconia has nectary stomata on the ovary apex. Meriania may release nectar through the anther connective, but has additional nectary stomata on the inner walls of the hypanthium. Brachyotum also has nectary stomata on the anther connectives, but these are distributed lengthwise along most of the connective. Blakea and Huilaea have nectary stomata located upon the dorsal anther connective appendages. Moreover, the nectar is probably supplied by large vascular bundles near the release area. In most species, nectar secretion is related to stomatal or epidermal nectaries and not filament slits as previously reported. All vertebrate-pollinated melastome flowers have petals that do not open completely at anthesis, thus forming a pseudo-tubular corolla, while closely related species that are bee pollinated have rotate or reflexed corollas.
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