I am launching a new study of phylogeography and the spatial scales of genetic differentiation and outcrossing depression in the Bay Area clade of Calochortus, to determine whether species endemic to serpentine have been derived from within more widely ranging, non-serpentine species, and whether poor seed dispersal has led to genetic differentiation and incipient mating barriers at small spatial scales, culminating in high species diversity, geographic cohesion of lineages, and parallel adaptive radiations in several traits across Calochortus as a whole. We are using AFLPs, a rapidly evolving and hypervariable set of genetic markers, to track genetic variation within and among Calochortus populations in northern California. This work follows earlier research on phylogenetic reconstruction in Calochortus with Tom Patterson. 

Terra Theim is examining the geographic scale of genetic differentiation in gap vs. understory species of Psychotria to test the idea that understory tropical trees with fleshy fruits differentiate and speciate at small spatial scales - and ultimately contribute a remarkably high fraction of rain-forest tree diversity - because they rely on sedentary forest-interior birds for seed dispersal. I am interested in recruiting a student to analyzed the spatial scales of genetic differentiation and incipient mating barriers in the Hawaiian lobeliads as well.

Kendra Millam is studying the phylogeography of the Trillium erectum complex, reconstructing the historical biogeography of this hallmark lineage of the southern Appalachians. Melissa Chung recently completed a phylogeographic study of the Oxytropis chartacea complex in eastern North America, showing that the federally endangered Fassett's locoweed (O. chartacea var. campestris) is most closely related to populations in Maine and the Maritime Provinces of Canada, and that all of these populations are closely related to some along the southern shore of Hudson Bay.
 

Photographs:  TOP - Portrait of the scientist as a young man among Nymphaea;sandstone escarpment, Auyán-tepui, one of the many plateaus of the Guayana Shield and home to many narrow endemics; Calochortus pulchellus (Liliaceae), member of a species-rich genus characterized by seeds with no apparent means of long-distance dispersal; and Trillium flexipes (Melanthiaceae), a wide-ranging, Midwestern element of the Trillium erectum complex, including several narrow endemics to the southern Appalachians and two other wide-ranging taxa (T. cernuum and T. erectum). Photograph of Calochortus pulchellus © 2000 Robert M. Case, reprinted with permission.