Novel genera of Parmulariaceae on Arecaceae from Brazil.

The ascomycetes placed in Parmulariaceae represent a diverse assemblage of biotrophic plant parasites. They usually produce discoid/scutellinioid stromata that are external to erumpent on living leaves of plants in the tropics. Disease symptoms are usually mild, and fungal structures are often cryptic on their hosts. These fungi are poorly known to science, and their classification has relied mostly on morphological features. There was a general lack of molecular data for taxa placed in this family, until recently, and morphological descriptions of many genera and species were brief and incomplete. Morphology remains the main source of information for taxonomic delimitation within the family. Here we follow a polyphasic approach, combining morphological, molecular, and host association information in order to elucidate the identity of three members of the Parmulariaceae found on samples of three neotropical palm species (Arecaceae), namely, (i) Acrocomia aculeata (macaw palm), (ii) Astrocaryum aculeatissimum (brejaúva), and (iii) Syagrus romanzoffiana (queen palm). Each palm species is a host for a novel species, each belonging to a new genus. The following names are proposed: (i) Concertinularia acrocomiae, sp. et gen. nov.-on macaw palm; (ii) Amphistromularia astrocaryi, sp. et gen. nov.-on brejaúva, and (iii) Labyrinthularia syagri, sp. et gen. nov.-on queen palm.