Systematics of the genusAuriculariawith an emphasis on species from the southeastern United States

[摘要] The genusAuriculariacomprises 10�?15 recognized species worldwide, and most are considered to have intercontinental to cosmopolitan distributions. Though regional field guides for the southeastern United States treat only one or two species, five species,A. fuscosuccinea, A. auricula-judae, A. mesenterica, A. polytricha,andA. delicata , have been recorded from the region. This study seeks to evaluate and revise current species concepts inAuriculariausing phylogenetic and morphological methods to better understand the species occurring in the southeastern United States. Historical collections from herbaria and fresh material from the field have been examined and sequenced at two loci, ITS and rpb2. Phylogenetic results indicate several diverse clades are in need of taxonomic revision. Previous reports ofA. auricula-judaein the southeastern U.S. likely represent a clade ofA. americana . Collections identified asA. delicataare found to be polyphyletic and distributed in four clades. Variation in the presence or absence of a medulla layer in some species, previously a key morphological character, has made it evident that additional characters are required to reflect the genetic diversity in the genus. A new taxonomic character, the schizomedulla, is discussed and shown to distinguish two novel species,A. subglabraandA. scissa , from the morphologically similar speciesA. delicata . A reticulate, merulioid hymenial surface can no longer be considered a character unique toA. delicata . Furthermore, ITS data from the voucher-specimen from which the genome ofA. delicatawas produced indicates this species isA. subglabra . The taxonomy and nomenclature ofPeziza nigricansis discussed and it is shown to be the earliest priorable name forA. polytricha sensu auct. amer. , and the new combinationAuricularia nigricansis proposed. We now recognize the following species ofAuriculariafrom the southeastern U.S.:A. americana, A. fuscosuccinea, A. mesenterica, A. nigricans,andA. scissa.

[学科分类] 植物学

[关键词] Agaricomycotina;Auriculariaceae;Auriculariales;Auricularia;Costa Rica;heterobasidiomycetes;jelly fungi;neotropical fungi;southeast U.S.;systematics;taxonomy