Fungalpedia – Note 2958, Karstiomyces
Karstiomyces J.F. Zhang & K.D. Hyde.
Citation when using this data: Zhang JF et al. 2023 – Fungalpedia.
Index Fungorum, Faceoffungi, MycoBank, GenBank, Fig 1.
Classification: Incertae sedis, Incertae sedis, Incertae sedis, Incertae sedis, Pezizomycotina, Ascomycota, Fungi.
Saprobic on dead culm of herbaceous plant. Sexual morph: Ascomata immersed, subglobose to basal laterally flattened, dark brown to black, solitary to gregarious. Peridium composed of several layers of hyaline to brown, thick-walled pseudoparenchymatous cells, arranged in textura globulosa. Hamathecium comprising branched, non-septate, filamentous pseudoparaphyses, anastomosing between and above the asci. Asci 8-spored, bitunicate, fissitunicate, cylindrical, pedicellate, apically rounded, with an ocular chamber. Ascospores overlapping to bi-seriate, oval to broadly fusiform, pale brown, septate, and constricted at the septa, verrucose. Asexual morph: Undetermined.
Notes: Karstiomyces is sister to Pseudopassalora with full bootstrap support (Zhang JF et al. 2023). Of eight reported genera in Eriomycetaceae, three (Eriomyces, Heleiosa, Neoheleiosa) are described with a sexual morph. However, Karstiomyces differs from these genera by its multi-septate, brown ascospores and the unique texture shape of the peridium (Kohlmeyer et al. 1996; Hyde et al. 2020b; Mortimer et al. 2021). Based on a megablast search of NCBI’s GenBank nucleotide database, the closest hits using the LSU sequence had highest similarity to Haudseptoria typhae (CBS 146790, GenBank NG_076711; identities = 782/805 (97%), no gaps), Heleiosa barbatula (JK 5548I, GenBank GU479787; identities = 819/852 (96%), 3 gaps (0%)), Italiofungus phillyreae (CPC 35566, GenBank MT223804; identities = 807/843 (96%), 2 gaps (0%)) and Neoheleiosa lincangensis (HKAS 111914, GenBank NG_075423; identities = 815/849 (96%), 1 gap (0%)). Closest hits using the SSU sequence had highest similarity to Heleiosa barbatula (JK 5548I, GenBank GU479787; identities = 872/904 (96%), 2 gaps (0%)) and Neoheleiosa lincangensis (strain HKAS 111914, GenBank NG_075423; Identities = 860/893 (96%), 3 gaps (0%)). Closest hits using the ITS sequence had highest similarity to Pseudopassalora gouriqua (CBS 101954, GenBank NR_160207; identities = 470/507 (93%), 5 gaps (0%)) and Italiofungus phillyreae (CPC 35566, GenBank MT223804; identities = 407/447 (90%), 10 gaps (2%)). No significant hits were obtained when the TEF1-α and Rpb2 sequences were used in blastn and megablast searches. Based on the morphological and phylogenetic analysis, Karstiomyces is introduced as a new genus to accommodate the type species Karstiomyces guizhouenbsis.
Type species: Karstiomyces guizhzouensis J.F. Zhang & K.D. Hyde.
Other accepted species: Species Fungorum – search Karstiomyces.
Figure 1 – Karstiomyces guizhzouensis (GZAAS 19-1754, holotype): a, b Appearance of ascomata on the substrate. c Vertical section through ascoma. d Section of peridium. e Pseudoparaphyses intermixed with asci. f, g Asci. h–l Ascospores. Scale bars: c = 50 µm, d–g = 20 µm, h–l = 5 µm.
References
Entry by
Jinfeng Zhang, Guizhou Provincial Institute of Tea, Guiyang 550006, People’s Republic of China, Guizhou Key Laboratory of Agricultural Biotechnology, Guizhou Academy of Agricultural Sciences, Guiyang 550006, People’s Republic of China, Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai 57100, Thailand.
Published online 14 August 2026