Hearty congratulations are extended to Elizabeth ‘Beth’ Kempton who successfully defended her doctoral dissertation and joins the ranks of Ph.D.s graduated and two new graduates with a Master's in Botany from the Claremont Graduate University Botany Program at Rancho Santa Ana Botanic Garden.
Kempton’s dissertation, titled “Systematics, character evolution and ecological diversification within Eriogonoideae s.s.” focused on this subfamily of the Wild Buckwheat family Polygonaceae. Her study included about 325 species in 20 genera, the vast majority of which occur in western North America. The group that Kempton studied includes the shrubby buckwheats (Eriogonum giganteum and E. grande) and California buckwheat (E. fasciculatum)—one of the most locally common components of the coastal sage scrub and chaparral plant communities.
A few species in her study include some Chorizanthe that occur in South America, on the other ‘side’ of the Tropics (i.e., the plants in this group do not occur in the Tropics). Kempton assembled a great deal of DNA sequence data to study the phylogeny (family tree) of these plants. She found that current classification does not match the family tree very well and was able to point to certain kinds of features that have misled previous workers about the group. Kempton’s work represents a quantum leap in our understanding of the history of these quintessential western plants. In conducting her research, Kempton used GIS climate mapping to ask whether a particular subgroup of these plants represents an adaptive radiation (i.e., a situation in which each species has evolved in association with adapting to a particular climate, soil type, etc.).
Kempton’s dissertation was supported in part by a Doctoral Dissertation Improvement Grant from the National Science Foundation and by several sources of research funds at Rancho Santa Ana Botanic Garden.
Summer’s Bounty Yields Two New Graduates with Master’s in Botany
On Tuesday, July 27, Carrie Kiel presented her research on the Mirandea Clade of the plant family Acanthaceae. Kiel’s work on plants within the Tetramerium lineage included seven species currently placed within four genera: Mirandea, Hoverdenia, Yeatesia, and Justicia. Members of this lineage grow on limestone substrates and occur almost exclusively in dry habitats in northeastern Mexico and southern Texas. One species is the outlier, inhabiting a broad geographical region of the southern United States in wetter habitats. This small group is remarkable for the range of flower variation in both form and color, suggesting divergent evolution in conjunction with their pollinators (bees, flies, butterflies and, perhaps, bats!). Although morphologically diverse in the shapes and sizes of their flowers, the shapes and sizes of their pollen and seeds are consistent and unique among the clades within the Tetramerium lineage.
Kiel traveled to the southern U.S. along the Gulf Region, into Texas, and Mexico to collect plant samples. She used molecular methods, as well as observations made under Scanning Electron Microscope (SEM) to test the relationships among her study group. As a result of her work, she was able to determine phylogenetic relationships among the species, which were also supported by an association within the geographic regions in which the plants occur. Her findings further elucidated the relationships among the species, such that some genera may be reassigned generic names. Forthcoming publications may show that Hoverdenia includes more species than previously thought. In the fall, Kiel will continue her graduate work as a doctoral student in the graduate program at Rancho Santa Ana Botanic Garden.
On Friday, July 30, Sula Vanderplank defended her master’s thesis that involved nearly five years of extensive fieldwork, which involved collecting samples for vouchered herbarium specimens, and databasing her findings to create a vascular flora of the greater San Quintín region of Baja California, Mexico.
Vanderplank fell in love with the area, located midway down the Baja Peninsula, and took the time to become conversant in Spanish in order to increase her effectiveness in her study. Countless trips to Baja, close collaboration with her colleagues in Mexico, resulted in the production of the flora.
This region is home to a diverse group of plants—many occur nowhere else in the world. When Vanderplank compared the flora documented in her study to historical records from the region—the adverse impact of agriculture and urbanization on this habitat were clear.
Her study of the perennial vegetation yielded distribution data for 140 species, which were evaluated to determine areas of significant species richness for native, rare and endemic taxa. While conducting her research, Vanderplank was actively engaged in collaborations with U.S. and Mexican botanists to earmark specific areas within the greater San Quintín region that merit significant conservation priority. She has made presentations in Spanish at symposia in Baja and continues to remain actively involved with her colleagues there. In the fall, Vanderplank will begin a Ph.D. program at the University of California, Riverside.
Congratulations to all three of our summer graduates! Beth Kempton (Ph.D.), Carrie Kiel (M.S.) and Sula Vanderplank (M.S.).