Assessment of historical Andreaea names from northwestern Argentina clarifies the taxonomy of ecostate Andreaea species in the Central Andes

Resumo

The genus Andreaea Hedw. remains poorly understood in the Andean region of South America, where species delimitation has historically been based on highly variable morphological characters. In this study, the type material of Andreaea arachnoidea, A. lorentziana, A. fragilis, and A. semisquarrosa, all described by Müller from northwestern Argentina based on collections made by Lorentz during the nineteenth century, was critically revised. Examination of specimens preserved at JE demonstrated that these names do not represent distinct taxa, but correspond respectively to A. rupestris, A. mutabilis, or A. acutifolia. Morphological variation observed among the studied specimens mainly involves habit, branching pattern, leaf orientation, and leaf acumination, characters strongly influenced by environmental conditions in high-Andean habitats. The reinterpretation of A. arachnoidea further demonstrated that the arachnoid structures mentioned in the protologue correspond to fungal hyphae associated with the gametophores rather than to intrinsic morphological features of the moss. The synonyms proposed here contribute to the taxonomic clarification of Andreaea in South America and reinforce the floristic affinities between the Central Andes and austral-temperate bryophyte floras. We designate lectotypes for all the studied names.