Research

Research Interests

Research in my lab emphasizes biodiversity through field and lab-based approaches that address phylogeny, pollination biology, biogeography, and ecology. My broad interests allow me to combine a variety of scientific approaches, such as DNA sequencing, field observations and surveys, and manipulative experiments, to attempt to explain the evolutionary history and ecology of various plant groups. Since 1994 I have developed and implemented various biodiversity research projects throughout the New World Tropics (especially Ecuador, Peru, Bolivia, Colombia, and Cuba). These projects have helped understand the distribution, taxonomy, and evolutionary relationships of critically endangered flora.

Since the time of Darwin naturalists and biologists used patterns of morphological variation among species to make inferences about relationships, and evolutionary processes such as natural selection and adaptive radiation. Traditional classifications are often incorrect for inferring relationships such as the presence of pouched flowers as a feature in closely related species in the flowering plant family Gesneriaceae (Figure 1). Results from our lab suggest that pouched flowers are independently derived in many unrelated lineages. Research in my lab aims to combine an ecological and field-based approach towards developing a classification that reflects the morphological similarity in related and unrelated lineages.

Figure 1. Possible pollination syndromes in Drymonia. (A) Drymonia ambonensis and (B) D. coriacea appear hummingbird adapted; note the hypocyrtoid (pouched) corollas and bright colors. (C) Drymonia turrialvae and (D) D. laciniosa appear bee adapted; note the campanulate corollas, fimbriate petal margins, and nectar guides.

My own fascination with floral diversification resulted from four years of living in the tropics and attempting to understand the relationships, classification, and biology of common plants that either had no name, or no intuitive generic boundaries, and from a desire to understand the interaction of the animals that visited them. One of the discoveries that I made in graduate school is that flowers of some species of Gesneriaceae are inverted, or resupinate, in orientation compared to those of related taxa (Fig. 2 A-D). Although inverted flowers have been mentioned prominently in the literature about orchids since Linnaeus (1780) and Darwin (1892), there are few phylogenetic based studies on the evolution of resupinate flowers.

Figure 2. Resupinate and non-resupinate flowers in the Gesneriaceae. A. Lateral view of resupinate flower ofGlossoloma subglabrum. B. Lateral view of non-resupinate flower of Glossoloma anomalum. C. Front view of resupinate flower of Crantzia cristata showing androecium on lower surface. D. Front view of non-resupinate flower of Drymonia sp. nov. showing androecium on upper surface.

All students in my lab are actively engaged in field and lab-based approaches. Some of our current research projects, papers, and presentations are listed below. Please visit my website to learn more about the students and their projects.

Currently Funded and Future Research

I am currently funded by two grants from the National Science Foundation to conduct research on the phylogeny and taxonomy of the genera Columnea and Drymonia. These grants have helped us discover that there are numerous transitions between bee-adapted and bird-adapted flowers and a remarkable diversity of flower shapes and colors. The shift between pollinators is often associated with flower shape. In particular, the presence of pouched or hypocyrtoid corollas (see Figure 1) are often good indicators of bird or anti-bee pollination. Hypocyrtoid flowers are independently derived in nearly every major Gesneriaceae clade from Central and South America. We are interested in understanding the biology of pouched flowers in speciation, diversification, and pollination biology.

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