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The systematic utility of sequences from two non-coding regions of plastid DNA, psbA-trnH and trnS-trnG, and one nuclear region, nrITS, was examined in an assessment of phylogenetic relationships among Neotropical sections of Bulbophyllum Thouars (Orchidaceae, Epidendroideae, Dendrobieae). The nrITS region was 6 to 7 times more variable than the two cpDNA regions. No major incongruencies between the nuclear and cpDNA datasets were detected. The combined analysis revealed a well-resolved phylogeny at sectional level based on both maximum parsimony and Bayesian approaches. Six sections of Bulbophyllum are recognized for the Neotropics. Five of these were pre-existent but needed to be recircumscribed and one is proposed as new. We did not find disagreements between maximum parsimony and Bayesian analyses, but the latter showed better resolved relationships between the sections, which are supported by morphological features. Of the two main clades of Neotropical Bulbophyllum species, one has two lineages and occurs predominantly north of the Equator. The second contains four lineages which are highly diverse in southeastern Brazil. Our results suggest a single colonization event in the Neotropics, from Africa to northern South America, followed by dispersion through the Andes to southeastern Brazil.

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Bulbophyllum section Didactyle comprises seven species, but distinction between these is often problematic. These species are pollinated by milichiid flies and air currents move the hinged labellum and press the pollinator against the gynostemium. The labellum structure is considered to be homogeneous and conservative for the genus. Therefore, the floral anatomy and micromorphology of B. section Didactyle were studied in order to identify characters useful for distinguishing the species. All species have sunken glandular trichomes on the abaxial surface of the sepals (possible osmophores) and a trilobed labellum, clothed with trichomes, with a secretory cavity in the callus that is bound by scale-like papillae. Of the c. 100 characters assessed, 25 varied between species, and each pair of species differed by at least four character states, mainly occurring on the labellum. The data presented allow for a distinction to be made between species and corroborates their grouping in B. section Didactyle, as proposed previously. The presence of osmophores and a nectary on the labellum is confirmed, although their structure is more diverse than anticipated. Moreover, structural differences between B. weddellii and the core of the section might be the result of the odour-mediated attraction of pollinators rather than flower morphology and thus phylogeny.

Most species in Melastomataceae have poricidal anthers related to specialised bee buzz-pollination, while some have anthers with large openings associated to non-bee pollination systems. We tracked the evolution of anther morphology and seed number on the Miconieae phylogenetic tree to understand the evolutionary shifts in such pollination systems. Anther morphometric data and seed number were recorded for 54 taxa. Pollinators (bees, flies, wasps) were recorded for 20 available species. Ancestral state reconstruction was made using Maximum Likelihood from nrITS sequences. We used phylogenetic eigenvector regressions to estimate phylogenetic signal and the adaptive component for these traits. Species pollinated by bees or bees and wasps tend to have smaller pores and fruits with more seeds. Species pollinated by flies or flies and bees and/or wasps tend to have larger pores and fruits with less seeds. Independent evolution occurred three times for anthers with large pores and twice for fruits with few seeds. We detected a phylogenetic signal in both traits, and negative correlated evolution between them. In actinomorphic small-flowered Miconieae, changes in anther morphology can be related to generalisation in the pollination system incorporating flies and wasps as pollinators and lessening the importance of buzzing bees in such process. Differences in pollen removal and deposition may explain differences in anther morphology and seed number in Miconieae.