Segregation of the New Lichen Genus Foraminella from Parmeliopsis

Abstract

A taxonomic study was conducted on Parmeliopsis in North America to examine the features which characterize the genus and its member species. Two of the species studied are retained in Parmeliopsis, while three are transferred to a new genus, Foraminella. Members of the genus Parmeliopsis have emergent, laminal to marginal pycnidia, short conidia which are generally bacilliform with one (or sometimes two) swollen areas, ellipsoid ascospores, whitish to light brown lower cortices, and thamnolic acid. Parmeliopsis aleurites forms isidia, while P. placorodia lacks both soredia and isidia. Foraminella has immersed, laminal pycnidia, falcate conidia, reniform to allantoid ascospores, light brown to black (less frequently whitish) lower cortices, and divaricatic acid plus either usnic acid or atranorin. All three North American species form soredia. Pored epicortices are present in the species of both genera. The name Parmeliopsis first appeared when Nylander (1861) recognized the Parmeliae placorodiae as a subgeneric group of Parmelia, and suggested the provisional name Parmeliopsis for the group. The member species were characterized as having short, simple sterigmata, an underside at least moderately covered with rhizines, and long, thin, curved conidia. Stizenberger (1862) then used the name Parmeliopsis for a subgroup of Parmelia, naming P. placorodia Ach. as the only example. The name Parmeliopsis was elevated to the generic level when a preprint of Lichenes Lapponiae orientalis was published by Nylander (1866). Sections were later proposed to deal with heterogeneity within Parmeliopsis. Gyelnik (1932) named section Viridifera to include the greenish-yellow species and section Pallidifera to encompass the gray species. In another attempt to organize the species of Parmeliopsis Hillmann (1936) suggested two sections, Curvoconidia and Rectoconidia, which were separated from each other on the basis of conidial shape. The publications by Gyelnik and Hillmann indicate that Parmeliopsis is not a homogeneous group. The North American species currently placed in Parmeliopsis therefore were examined to determine the extent of diversity present within the genus.