Lucinda McDade. Associate Professor, Department of Plant Sciences and Ecology & Evolutionary Biology; Curator of the Herbarium. Ph.D., Duke University. (30% Research in Plant Sciences)
Phylogenetic systematics and reproductive biology of flowering plants.

I am a phylogenetic biologist, with research objectives focused on advancing knowledge of flowering plants, including both existing patterns of diversity and the historical underpinnings of these patterns. My interests are both empirical (which species occur where, what are their characteristics and how are they interrelated?) and theoretical (specifically related to hybridization and phylogenetics). The latter has led to a third focus on processes at and near the species level.

Documenting diversity, especially tropical diversity, is woefully far from complete. A significant portion of my research is directed toward increasing knowledge of Neotropical Acanthaceae, a large (>4,000 species) and poorly known plant family. I am also deeply interested in higher level relationships within Acanthaceae (and within the Asteridae to which this family belongs). My lab is involved in a study of phylogenetic relationships among Acanthaceae using molecular and morphological data. This study has been geared toward testing ideas based on morphology about relationships within the family.

The second main theme of my work is the theory and practice of systematics,with an emphasis on the impact of hybrids on phylogenetics. It has been argued that hybridization is so common among plants that it is not possible to use phylogenetic techniques to study plant relationships. This is because existing phylogenetic methods assume that evolution has been by the divergent branching of lineages rather than by anastomoses. My work has used hybrids of experimental origin to address empirically questions about the impact of hybrids: If hybridization is as rampant as many botanists believe, is phylogenetic analysis likely to give anything close to the right answer? Can phylogenetic analysis help us to recognize hybrids?

My work with hybrids reflects my interest in processes near the species level and in how biologists approach problems at this level. As a process that occurs just below the species level, speciation can be seen as hybridization's 'mirror image'. Research on plant populations on southern Arizona's "Sky Islands" (i.e., the tops of mountains that provide habitats for plants and animals that cannot survive in the desert below) involves using them as natural experiments in differentiation and speciation. We have begun by looking at four species whose biological characteristics we hypothesize to have resulted in their sky island populations being relatively more or less differentiated. Interest in processes near the species level is also at the core of my continuing interest in plant reproductive biology. I have combined data regarding plant pollinator relationships with a phylogenetic approach to ask questions regarding the evolution of these relationships, and conducted research on several aspects of the relationship between plants and hummingbirds: parasitism of resource-rich flowers by non-pollinators, dynamics of pollen flow and deposition on compatible stigmas, evolution of sexual systems.

McDade, L.A. 1990. Hybrids and phylogenetic systematics I. Patterns of character expression in hybrids and their implications for cladistic analysis. Evolution 44:1685-1700.

McDade, L.A. 1992. Pollinator relationships, biogeography, and phylogenetics. BioScience 42:21-26.

McDade, L.A. 1992. Hybrids and phylogenetic systematics II. The impact of hybrids on cladistic analysis. Evolution 46:1329-1346.

McDade, L.A., K.S. Bawa, H.A. Hespenheide, G.S. Hartshorn (eds.). 1994. La Selva: Ecology and Natural History of a Tropical Rainforest, Chicago Univ. Press, Chicago, IL, 486 pp.

McDade, L.A. 1995. Hybridization and phylogenetics. Pp. 305-331 in Experimental and Molecular Approaches to Plant Biosystematics, P.C. Hoch and A.G. Stephenson (eds.), Missouri Botanical Garden.

Daniel, T.F. and L.A. McDade. 1995. Additions to the Acanthaceae of Panama. Annals Missouri Botanical Garden 82:542-548.

McDade, L.A. 1995. (in press). Species concepts and problems in practice: Insight from botanical monographs. Systematic Botany 20:606-622.