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In this study, we investigated the pollination ecology and floral lip morphology of Gongora bufonia Lindl., an epiphytic orchid from tropical forest, to better understand the peculiarities of its unusual pollination mechanism. Field observations on pollination were performed and floral lip samples were prepared for anatomical, histochemical, and ultrastructural analyses. Male Eufriesea violacea (Blanchard) bees use the second and third pairs of legs to hold on the epichile and collect the fragrance in the hypochile region. During this process, the bee slips and falls on the column and receives the pollinarium, which is attached to the rear edge of the bee’s scutellum. A subsequent visit (usually to another flower) and fall through the flower may result in insertion of a pollinium into the stigmatic slit at the apex of the column. The fragrance production occurs in the hypochile region, specifically in the papillose epidermal cells and in the subepidermal parenchyma layers. The wax production occurs in the epichile region, exclusively in the epidermal cells. The cells of both regions, hypochile and epichile, have ultrastructural features of lipophilic secretion. The slippery quality of the epichile epidermis is due to wax deposits; this is probably essential to the pollination mechanism of G. bufonia.

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Th e genus Punctelia has been traditionally characterized by the type and distribution of pseudocyphellae, medullary chemical substances and the shape of conidia, whereas its species have been distinguished using mainly the shape, location, abundance and size of pseudocyphellae. Given that Punctelia is not monophyletic, additional studies are needed to determine its current delimitation. Th e present study used conventional techniques for structural studies using optical and scanning electron microscopy in order to describe and compare the structure and ontogeny of the pseudocyphellae of fi ve species of Punctelia. Th e main diff erences among the studied species involve the type of pseudocyphellae development, the presence or absence of an epicortex cover and the organization and structure of the upper cortex. In one group of species the pseudocyphellae are formed from the outside to the inside of the thallus; in the other group, pseudocyphellae formation begins with the organization of medullary hyphae into circular groups in specifi c places. Th e present study contributes to the understanding of the structure and ontogeny of pseudocyphellae.