Associate Curator, William L. Brown Center
Research Interests
• Identification, quality control, and systematics of medicinal plants
• Malagasy flora
• Molecular systematics
• Botanical nomenclature
• Revisionary and phylogenetic studies
• Chemical variability in medicinal plant species
Web Page: MBG
1.) Morphology and Systematics of the Genus Ptelea. Ptelea is a genus of trees belonging to the citrus family; it is native to the eastern and southern portions of North America, where it has been used in traditional herbal medicine. The last revision of this genus, in 1962, recognized three species. Two of these were local southwestern species; P. trifoliata was broadly defined as a widespread and variable species, with five subspecies most of which were divided into multiple varieties. Chemical studies have reported that different subspecies have different chemistry. It is questionable whether the current taxonomic treatment is very good. On one hand, recognition of numerous slightly different forms as varieties and subspecies is often not biologically meaningful; on the other hand, some of these “subspecies” may actually be different species that were wrongly lumped together. This kind of confusion can obscure the results of studies of a plant’s medicinal activities. We will seek to resolve the question by doing a phenetic study, in which measurements will be taken from many specimens and the data will be run through a computer program to see how many separate clusters they group into. A list of important characters has been chosen, some data have been taken, and herbarium loans of southwestern material have been obtained. Using a computer database, the participating student will take measurements and notes from each of several hundred specimens, then observe or help with data analysis. Knowledge of the basic parts of a plant and good attention to detail are needed; no statistical background is necessary. It is expected that the participating student will be listed as a co-author on a published manuscript.
2.) SEM-based Authentication of Medicinal Plants. Consumer products made from medicinal plants are required to be correctly identified, but independently confirming the botanical identity of raw materials is sometimes difficult or impossible. Methods include chemical and DNA-based authentication, but many genera have not been subjected to enough study to identify chemical markers (if any exist) that reliably separate desired from undesired species. A potential alternative involves the use of scanning electron microscope (SEM). Using the genus Grindelia as a model, a student will attempt to develop reliable means of distinguishing the four commercially used medicinal species from unofficial and other undesirable species native to the same areas. The student will confirm the identity of herbarium specimens using keys, SEM images of fragments taken from specimens, and evaluate the potential for identification of species.
3.) Sustainable Local Medicinal Plant Production: What “Foodshed” is Required? Relocalization is an increasingly popular concept among the public in some regions, in response to economic difficulties and growing recognition of the ecological consequences of globalization. American researchers have recently begun to think in terms of a “foodshed,” comparable to a watershed, to determine whether, and how much, land available in the vicinity of a given city would suffice to feed its population. Medicinal plants, which require far less space per capita than staple food crops, have enormous potential to be locally and affordably produced to supply local businesses and consumers. The student will determine from literature what medicinal plants are currently popular in the U.S. market and the quantities consumed, what plants considered suitable for each popular use can be grown in selected regions, and (with the aid of limited field collections) what their approximate potential yields are. Using a range of assumptions about growing conditions and per-capita consumption, the student will calculate how much land would be required for urban areas of specified size to produce sufficient raw materials to replace at least 90% of their average current consumption of botanical dietary supplements.
Selected Publications
• Applequist, W.L., and D.E. Moerman. 2011. Yarrow (Achillea millefolium L.): a neglected panacea? A review of ethnobotany, bioactivity, and biomedical research. Economic Botany 65:209–225.
• Applequist, W., illustrated by B. Alongi. 2006. The identification of medicinal plants: a handbook of the morphology of botanicals in commerce. American Botanical Council, Austin, TX.
• Applequist, W. L. 2005. Root anatomy of Ligusticum species (Apiaceae) sold as osha compared to that of potential contaminants. Journal of Herbs, Spices and Medicinal Plants 11(3):1–11.
• Applequist, W. L., D. J. McGlinn, M. Miller, Q. G. Long, and J. S. Miller. 2007. How well do herbarium data predict the location of present populations? A test using Echinacea species in Missouri. Biodiversity and Conservation 16:1397–1407.