Redisposition of apiosporous genera Induratia and Muscodor in the Xylariales, following the discovery of an authentic strain of Induratia apiospora.

Background: The genus Induratia is based on Induratia apiospora, a xylarialean pyrenomycete from New Zealand with clypeate uniperitheciate stromata, hyaline apiospores and a nodulisporium-like anamorph. However, because of the lack of DNA data from the generic type, its phylogenetic affinities have remained unresolved. Recently, two fungal species with teleomorphs strikingly similar to Induratia were discovered in Thailand. However, they did not produce an anamorph and were found to be phylogenetically close to the species classified within the hyphomycete genus Muscodor, which was described after Induratia. Therefore, in 2020 the species of Muscodor were transferred to Induratia, and a new family Induratiaceae was proposed.

Results: We have encountered an unpublished ex-holotype strain of Induratia apiospora among the holdings of the ATCC collection, enabling detailed morphological and molecular phylogenetic investigations. We observed the characteristic nodulisporium-like anamorph described in the original publication. Phylogenetic analyses of multigene sequence data revealed a close relationship of Induratia apiospora to the Barrmaeliaceae, while a close relationship to the Induratia species formerly classified within Muscodor was rejected.

Conclusions: We here classify Induratia apiospora within the Barrmaeliaceae and consider Induratiaceae to be synonymous with the former. As the holotype specimen of Induratia apiospora is apparently lost, an isotype specimen from WSP is selected as lectotype. We also propose that the genus Muscodor is resurrected within the Xylariaceae, and formally transfer several Induratia species to Muscodor.