Theissenia Maubl., Bull. Soc. mycol. Fr. 30(1): 52 (1914)

Index Fungorum number: IF 5418; MycoBank number: MB 5418; Facesoffungi number: FoF 02976; 1 species with sequence data.

Type species – Theissenia pyrenocrata (Theiss.) Maubl.

Notes – Theissenia has a conspicuous central bulge or umbo in the perithecium and early dissolving asci. Ju et al. (2007) accepted the genus in Xylariaceae based on its nodulisporium-like asexual morph and act and tub2 phylogeny. Læssøe et al. (2013) accepted it in Graphostromataceae because of its nodulisporium-like asexual morph and close relationship to Biscogniauxia. Daranagama et al. (2018) and Wendt et al. (2018) accepted the genus in Xylariales genera incertae sedis. A recent study by De Long et al. (2019) placed the genus in Hypoxylaceae.

Species

  • Theissenia pyrenocrata