A Rediscovery of Arachnopeziza fitzpatrickii Korf (Arachnopezizaceae, Leotiomycetes)

In 2019, Arachnopeziza fitzpatrickii, a species previously known from only three collections, was collected in Massachusetts. The species is unusual in Arachnopeziza in that it consistently produces fascicles of hairs at the margin of the apothecia, a character that led Korf, when describing the species, to consider that it could belong to genus separate from Arachnopeziza This specimen of A. fitzpatrickii was examined morphologically in a living and dead state, and two gene regions (ITS and LSU) were sequenced for phylogenetic analyses. The results of our phylogenetic analyses indicate that the genus is polyphyletic. Arachnopeziza fitzpatrickii is recovered in Arachnopeziza sensu stricto though it occupies an isolated position in the genus distant from other species producing fascicles of hairs. Observations of our specimen are largely in agreement with the original and updated published descriptions of A. fitzpatrickii, with only a few features differing; these disagreements are likely attributable to the earlier descriptions being based on observations of dead material. Comparisons are also provided of all species in Arachnopeziza producing fasciculate hairs, whether marginal or elsewhere on the receptacle.