Discussion on taxonomy of the fern genera Crepidomanes and Polyphlebium (Hymenophyllaceae) in Argentina and south-eastern South America, and description of a new local variety for Crepidomanes pyxidiferum

Abstract

The fern genera Crepidomanes and Polyphlebium are clearly distinct, yet often confused in the wild and in collections. Morphological and molecular investigations were performed to find taxonomic characters for discriminating species occurring in southeastern South America (southern Brazil and northeastern Argentina). Our results show that the genus Polyphlebium is represented in the area by two species: Polyphlebium angustatum and Polyphlebium diaphanum. In addition P. diaphanum is a pantropical species that includes as synonyms neotropical Polyphlebium hymenophylloides and palaeotropical Polyphlebium borbonicum. We also show that southeastern South American Trichomanes emarginatum is a local variety of Crepidomanes pyxidiferum, here named C. pyxidiferum var. australe. A key for the species is provided and new taxonomic treatments are discussed.