A Taxonomic Re-evaluation of Specimens of the Genus Caloplaca in the E.L. Stover Herbarium of Eastern Illinois University

The genus Caloplaca is the largest genus in the family Teloschistaceae. The 103 species in the genus greatly outnumber any other in the family. Lichens of the genus Caloplaca are usually orange to orange-yellow in color, and range from crustose to subfoliose in form. The orange color is due to an anthraquinone, parietin, the location of which is taxonomically important in this genus of lichens. In some species it occurs only in the apothecia, while in others it is found in both the apothecia and thallus. The spores of this genus are polarilocular, and the width of the isthmus is also of great taxonomic importance. These lichens are typically found in dry open areas on rocks, wood, and tree bark. The name Caloplaca was given to this group of organisms in 1860 by Fries (Rudolph, 1955). This project has been done in an attempt to re-evaluate and re-identify the Caloplaca specimens in the E.L. Stover herbarium of Eastern Illinois University. This re-evaluation and re-identification is necessary because of a lack of access to the literature on this genus until recently. Additionally, specimens were collected over a period of almost twenty years, and each specimen was identified at or near the time of collection. The considerable number of Caloplaca specimens that have been accumulated permit a comparative study at this time. A total of fifty-seven specimens from the E.L. Stover herbarium were examined. Twenty-two of the specimens were collected in Illinois, while thirty-one were collected from other states, and two were collected from Puno, Peru. Two specimens from the collection were unidentified. These two specimens lacked apothecia and spores. Since spore characteristics are one of the most important aspects of species determination, no conclusions could be reached for these two specimens. Twenty-three of the fifty-seven specimens were misidentified. The species represented in the herbarium, after annotation, and the specimen total for each, follows: Caloplaca aurantiaca (4), C. cerina (6), C. cinnabarina (2), C. citrina (2), C. elegans (6), C. feracissima (2), C. ferruginea (3), C. festiva (2), C. flavovirescens (10), C. fraudans (1), C. holocarpa (2), C. lactea var. americana (1), C. laetea (2), C. lobulata (2), C. microphyllina (5), C. murorum (1), C. saxicola (2), C. sideritis (2)