While much of the flora of the Great Smoky Mountains National Park has been extensively studied, the lichens have been somewhat neglected. Degelius\u27 Lichen Flora of the Great Smoky Mountains (1941) is the first, and until now the only extensive study of the lichens of this area. Sharp (1930) mentions Gyrophora dillenii (=Umbilicaria mammulata) from Mt. LeConte. Cain (1935), Mozingo (1954), Sierk (1958), and Hale (1961) mention several species from the Smokies. Mozingo (1961) gives keys to the genus Cladonia both in Eastern Tennessee and in the Great Smoky Mountains.
The descriptions and keys in this study have been compiled from personal examination of lichen specimens from the Smokies and from the following sources in the literature: Hale (1961), Howard (1950), Llano (1950), Sierk (1958), and Thomson (1950 and 1963). These keys are strictly preliminary as they are based on a limited amount of material from a limited area and do not include species reported by others, which the author has not seen. For this reason they probably are not adequate for other areas. If further collecting is done other species may possibly be added.
The substrates given for each species following the descriptions are those most frequently observed by the author in the Smokies. Some species are occasionally found on other materials. The algae reported in the descriptions were not identified by the investigator but are those reported in the literature.
Where color tests have been used in the keys or descriptions the reagents used are:
P = paraphenylenedimine
K = KOH (potassium hydroxide)
C = chlorine bleach
The reactions of a lichen to color tests are recorded as positive (+) or negative (-). In a positive test there is a color change while in a negative test there is no color change. These color tests are made on the cortex or medulla of the thallus. Color tests are useful in distinguishing between some genera and some species.
All specimens examined are from the Great Smoky Mountains National Park. They include specimens which were already in the Herbarium of The University of Tennessee as well as recent collections by the investigator which are now on deposit in the Herbarium of The University of Tennessee. A map of collection areas is included in the appendix together with a list of the species observed and a list of the species reported by others but not seen in the present study