Date of Award

Spring 1-1-2016

Document Type

Thesis

Degree Name

Master of Science (MS)

First Advisor

Erin A. Tripp

Second Advisor

Patrick Kocioleck

Third Advisor

Nolan Kane

Abstract

The genus Xanthoparmelia belongs to one of the largest and most species-rich foliose lichen families - Parmeliaceae. It occurs in generally arid regions around the world and is particularly abundant in southern Australia, South Africa, regions of northern South America, Mexico, and the southwestern U.S.A. (Elix 1986; Hale 1990). In the United States, Xanthoparmelia is extremely common in the state of Colorado and undoubtedly plays a significant ecological role. Since the late 18th century, scientists have described numerous species in this genus. Over the years it has become increasingly apparent that Xanthoparmelia is difficult to identify to a species level based on macro and micro morphology, leading to repeated descriptions of the same species, ambiguous keys, and other taxonomical challenges. It was not until chemistry started becoming a taxonomic tool that it became possible to better identify species with accuracy. While there are still some discrepancies that arise when using traditional methods of morphology-based identification with chemical information, it has become clear that the latter has proved to be an invaluable research tool to lichenology. However, achieving balance between merging traditional morphological keys and more chemical data has proved to be a delicate process. The following study emphasizes the use of Thin Layer Chromatography (TLC), protologue descriptions, distribution maps, and examination of type specimens to delimit Xanthoparmelia species in Colorado. Using the University of Colorado Herbarium (COLO) collection in addition to collections made by the author, a total of 18 species belonging to five different chemical groups are here recognized as occurring in Colorado. Two new synonyms are here proposed: X. angustiphylla with X. conspersa and X. arseneana with X. novomexicana. In addition, two names have been excluded from the list of Colorado species: X. taractica and X. hypopsila. A dichotomous key followed by a treatment of these 18 species (including type citations, morphological descriptions, and chemical information) is included. This treatment is the first to focus solely on this abundant yet taxonomically challenging genus in Colorado. It will be useful to a variety of users ranging from seasoned lichenologists to amateur natural historians interested in Colorado lichen biota.

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