Studies on Parmelia subgenus Parmelia

At least 250 distinct species, most of which occur in the tropics, are included in Parmelia subgenus Parmelia. They are generally characterized by lobes that are narrow (0.5-4.0 mm. wide), sublinear to subirregular, and often apically truncate. The apothecia are adnate and usually imperforate, and there are rhizines over all or most of the lower surface. This broadly delimited group has usually been called section Hypotraehyna Vain., but we propose to recognize it as a subgenus, subgenus Parmelia, typified by P. saxatilis (L.) Ach. Subgenus Parmelia is coordinate with subgenus Amphigymnia (Vain.) Dodge, the broad-lobed Parmelias, and subgenus Xaiitkoparmelia (Vain.) Hale, comb, no v., based on section Xanthoparmelia Vain. (1890, p. 60), with Parn elia conspersa (Ach.) Ach. as the type species. The Xanthoparmelias are similar in configuration to many species in subgenus Parmelia, but they differ in being saxicolous, always containing usnic acid, and having simple rhizines. The brown Parmelias (sections Melanoparmelia Zahlbr., Vainioellae Gyel., and Olivascentes (Hue) Hillm.) are excluded from subgenus Parmelia, although we have not yet decided on their exact position in the genus. In the course of preparing a world monograph of subgenus Parmeliat we have examined the types of most of the described species and reevaluated the subgeneric classification. This preliminary study will present the outlines of a new sectional classification, descriptions of 52 new species, 2 new combinations, and 4 new names, and preliminary keys to the species in the major sections. A final monograph must await more extensive study of general herbarium material as well as field work, since many species are still known only from their type localities. This study has been made possible by the prompt and generous cooperation of the curators and directors of museums and university herbaria in lending type specimens and other valuable collections and in rendering assistance and providing facilities for study during visits. They include Dr. Sten Ahlner (Naturhistoriska Riksmuseet, Stock-