CBS 197.64 is a culture of Atropellis piniphila, deposited by J.C. Hopkins, isolate 61. Hopkins (Canadian Journal of Botany 39: 1521-1529, 1961) obtained isolates he identified as A. piniphila from Pinus contorta from both germinating ascospores and from diseased wood. There is no published record of the source of isolate 61, apart from that it was from one of Hopkins isolates from Alberta.

A genome from CBS 197.64 was deposited in JGI by Richard Hamelin, University of British Columbia. Sequences for all 15 genes used by Johnston et al. 2019 (IMA Fungus 10(1): 1-22, 2019) were extracted from this genome, incorporated into a concatenated alignment including the isolates reported by Johnston et al. (2019), and a phylogeny generated using the methods of Johnston et al. (2019).

This phylogeny clearly places CBS 197.64 in Hamatocanthoscyphaceae.

The culture was presumably correctly identified, as it was deposited by J.C. Hopkins who published several papers on this fungus in the early 1960's. The type species of Atropellis is A. pinicola. Ecologically and macroscopically A. pinicola and A. piniphila are very similar. They differ in ascospore size, filiform (32-63 x 1.5-3 um) in A. pinicola, oblong-elliptic (16-28 x 4-7 um) in A. piniphila. No DNA sequence data is available for A. pinicola, to provide phylogenetic confirmation of the generic relationship.

Atropellis is at present placed in Godroniaceae (Index Fungorum 2020), but without genetic support (Jaklitsch et al. 2016, Syllabus of Plant Families). As was shown by Partel et al. (Fungal Diversity 82: 183-219, 2017) in their study of encoelioid fungi, taxonomic concepts of Leotiomycetes with erumpent, leathery, dark walled apothecia have been developed largely on the basis of macroscopic appearance. These authors found that the fungi traditionally placed in Encoelia and Encoelioideae to be widely distributed across eight different lineages within the Leotiomycetes, including Godroniaceae. Such a morphology has clearly evolved multiple times. The phylogentic position of A. pinicola needs confirming, as does the generic relationship between A. pinicola and A. piniphila.

A. piniphila has a macromorphology nothing like any other known Hamatocanthoscyphaceae. Interestingly, Pinus-associated Infundichalara and Xenopolyscytalum species do belong in this family. Is it possible that if CBS 197.64 was isolated from plant tissue rather than ascospores, that it is in fact a pine-associated Infundichalara or Xenopolyscytalum sp. the conidia of which were by chance in the vicinity of the Atropellis piniphila canker?