title: The rust genus Frommeella revisited: a later synonym of Phragmidium after all.
abstract: Frommeëlla (Phragmidiaceae, Pucciniales, Basidiomycota), which currently includes two species and is typified by F. tormentillae, causes rust on members of tribe Potentilleae (Rosaceae). The genus has been distinguished from Phragmidium on the basis of having only one germ pore per teliospore cell rather than two or three and by aecial characters. Phylogenetic analyses of both currently accepted Frommeëlla spp. with nLSU rDNA data suggest that Frommeëlla was derived from within a clade representing Phragmidium. Thus Frommeëlla should be considered to be a later generic synonym of Phragmidium. Analyses also indicate that Frommeëlla tormentillae on Potentilla species includes two taxa recognized herein as Phragmidium potentillae-canadensis and P. tormentillae. Frommeëlla mexicana on Potentilla spp. formerly classified in Duchesnea, is distinct from but sister to the other two species. Based on data regarding type specimens that were presented in a study by McCain and Hennen, the new combination Phragmidium mexicanum is proposed as the correct name for this species. Necessary studies of original material were made, and Phragmidium potentillae-canadensis is lectotpyified and epitypified. Although considered and expanded here, further examination of species boundaries and host ranges of the fungi formerly classified in Frommeëlla is warranted.
authors.affiliation: Systematic Mycology & Microbiology Laboratory, USDA-ARS, B010A, 10300 Baltimore Avenue, Beltsville, Maryland 20705, USA.
authors.forename: Hye Young
authors.initials: HY
authors.lastname: Yun
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Minnis
authors.forename: Young Ho
authors.initials: YH
authors.lastname: Kim
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Castlebury
authors.forename: M Catherine
authors.initials: MC
authors.lastname: Aime
mesh_terms: D001487:Basidiomycota / Q000145:classification* / Q000166:cytology / Q000648:ultrastructure; D010802:Phylogeny