By Jeremy W. Howland, Laura Briscoe
Mar 31 2023
In early March of this year Chicita Culberson, whose work has been foundational to our understanding of lichen chemistry, passed away. Chicita Culberson was born on November 1, 1931 in Philadelphia and graduated with high honors from the University of Cincinnati in 1953. She continued her education at the University of Wisconsin receiving her master’s degree in 1954. Her work on lichens began after meeting her lifelong partner and husband, Bill Culberson.
In 1955 they both moved to North Carolina at Duke University where she began her long-running work on lichen metabolites, secondary chemical compounds produced by lichens that can have various biological atributes and can be essential for distinguishing similar-looking species. She received her PhD from Duke in 1959 and over the next sixty years was a research associate with her own self-funded lab. In 1969, she published Chemical and Botanical Guide to Lichen Products, which for the first time coalesced a chemical summary of all the known lichen substances and their occurrences.
Through her extensive research career, Chicita pioneered and standardized the use of thin-layer chromatography (TLC). Chromatography is used to separate lichen metabolites into their individual chemical components. Lichen TLC is typically done on a sheet of glass coated with a thin layer of adsorbent material, usually silica. A solvent is drawn up the plate via capillary action, and the lichen metabolites ascend the plate at different rates, allowing each individual compound to be distinguished. Before the 1950s, the methods used to identify lichen metabolites were time-consuming and non-standardized. The use of TLC to identify lichen metabolites was standardized by Chicta in a series of papers in the 1970s, and was accepted by the scientific community. She continued studying and cataloguing lichen chemistry, updating and revising her work until her retirement in 2019. In 1993 she was awarded the Acharius medal by the International Association for Lichenology for her lifetime achievements in lichenology.
Lichenologists now have a much easier and efficient way to identify these compounds that is still ubiquitous today because of Chicita’s research. TLC is still vital in how we catalogue and distinguish species by chemical profiles, along with modern molecular genetics. Anyone who has described a new lichen species in the past 50 years or engaged in serious lichen identification work has likely used these same methods.
Chicita was known for her soft-spoken attitude and willingness to help those learning the art of TLC. A genus of lichenized fungi, Culbersonia, was named in honor of Chicita and her husband Bill in 2000. Chicita and Bill also worked together to circumscribe a new genus in 1968, Cetrelia. Bill named one species after her, Cetrelia chicitae. Her legacy will live on through these eponymous honors, the taxa she named, and the methods she pioneered.
