Fungalpedia – Note 2422, Pseudojahnula
Pseudojahnula. W. Dong, H. Zhang & K.D. Hyde.
Citation when using this data: Dong W et al. 2020 – Fungalpedia, Ascomycota.
Index Fungorum, Facesoffungi, MycoBank, GenBank, Fig 1
Classification: Aliquandostipitaceae, Jahnulales, Incertae sedis, Dothideomycetes, Pezizomycotina, Ascomycota, Fungi
Saprobic on submerged wood. Sexual morph: Ascomata solitary or gregarious, erumpent, become superficial with base remaining immersed, subglobose, obpyriform or almost conical, hyaline and then metallic grey, coriaceous, with ostiolate papilla, with algal associations. Peridium comprising several layers of relatively large, hyaline, thin-walled, angular cells and covered with sparse hyaline hairs. Pseudoparaphyses numerous, trabeculate, filamentous, hyaline, septate, unbranched between the asci, branching and anastomosing above. Asci 8-spored, bitunicate, fissitunicate, obclavate, pedicellate, with an ocular chamber and faint ring. Ascospores bi- to tri-seriate near the base, overlapping uniseriate near the apex, l-septate, light brown, ellipsoid-fusiform, surrounded by a mucilaginous sheath, which is wavy in outline. Asexual morph: Undetermined.
Notes: Jahnula potamophila is morphologically closest to Ascagilis bipolaris in ascospore size, but differs by narrow mucilaginous sheath which is wavy in outline (Hyde and Goh 1999b; Hyde and Wong 1999). Both species cluster distantly in Jahnulales. The phylogenetic placement of J. potamophila is unstable, it clustered with Jahnula sensu stricto clade with low bootstrap support (Huang et al. 2018), but had good affinity in Hyde et al. (2017). With Megalohypha aqua-dulces and our new sequences added in the order,
J. potamophila clustered with M. aqua-dulces with moderate bootstrap support (Hyde et al. 2019).
Jahnula potamophila has hyaline to metallic grey ascomata, a several-layered peridium comprising hyaline cells and covered with sparse hyaline hairs, obclavate asci with an ocular chamber and faint ring, and ascospores surrounded by a wavy mucilaginous sheath (Hyde and Wong 1999). These characteristics differ from Jahnula, therefore, Pseudojahnula is introduced to accommodate J. potamophila.
Type species: Pseudojahnula potamophila (K.D. Hyde & S.W. Wong) W. Dong, H. Zhang & K.D. Hyde.
Other accepted species: Species Fungorum – search Pseudojahnula.
Figure 1 – Pseudojahnula potamophila (F111). a Ascomata attached to the wood with broad hyphae. e, h Ascospores. Scale bars: a, c = 200 µm, b, d–j = 20 µm.
References
Huang SK, Maharachchikumbura SSN, Jeewon R, Bhat DJ, Chomnunti P, Hyde KD, Lumyong S (2018) Morphological and molecular taxonomy of Jahnula dianchia sp. nov. (Jahnulales) from submerged wood in Dianchi Lake. Yunnan China. Mycol Prog 17:547–555
Hyde KD, Goh TK (1999b) Tropical Australian Freshwater Fungi. XVI. Some new melanommataceous fungi from woody substrata and a key to genera of lignicolous loculoascomycetes in freshwater. Nova Hedwigia 68:251–272
Hyde KD, Norphanphoun C, Abreu VP, Bazzicalupo A, Chethana KWT, Clericuzio M, Dayarathne MC, Dissanayake AJ, Ekanayaka AH, He MQ, Hongsanan S, Huang SK, Jayasiri SC, Jayawardena RS, Karunarathna A, Konta S, Kusan I, Lee H, Li J, Lin CG, Liu NG, Lu YZ, Luo ZL, Manawasinghe IS, Mapook A, Perera RH, Phookamsak R, Phukhamsakda C, Siedlecki I, Soares AM, Tennakoon DS, Tian Q, Tibpromma S, Wanasinghe DN, Xiao YP, Yang J, Zeng XY, Abdel-Aziz FA, Li WJ, Senanayake IC, Shang QJ, Daranagama DA, de Silva NI, Thambugala KM, Abdel-Wahab MA, Bahkali AH, Berbee ML, Boonmee S, Bhat DJ, Bulgakov TS, Buyck B, Camporesi E, Castaneda-Ruiz RF, Chomnunti P, Doilom M, Dovana F, Gibertoni TB, Jadan M, Jeewon R, Jones EBG, Kang JC, Karunarathna SC, Lim YW, Liu JK, Liu ZY, Plautz HL Jr, Lumyong S, Maharachchikumbura SSN, Matocec N, McKenzie EHC, Mesic A, Miller D, Pawlowska J, Pereira OL, Promputtha I, Romero AI, Ryvarden L, Su HY, Suetrong S, Tkalcec Z, Vizzini A, Wen TC, Wisitrassameewong K, Wrzosek M, Xu JC, Zhao Q, Zhao RL, Mortimer PE (2017) Fungal diversity notes 603–708: taxonomic and phylogenetic notes on genera and species. Fungal Divers 87:1–235
Hyde KD, Tennakoon DS, Jeewon R, Bhat DJ, Maharachchikumbura SSN, Rossi W, Leonardi M, Lee HB, Mun HY, Houbraken J, Nguyen TTT, Jeon SJ, Frisvad JC, Wanasinghe DN, Lücking R, Aptroot A, Cáceres MES, Karunarathna SC, Hongsanan S, Phookamsak R, de Silva NI, Thambugala KM, Jayawardena RS, Senanayake IC, Boonmee S, Chen J, Luo ZL, Phukhamsakda C, Pereira OL, Abreu VP, Rosado AWC, Bart B, Randrianjohany E, Hofstetter V, Gibertoni TB, Soares AMdS, Plautz HL, Sotão HMP, Xavier WKS, Bezerra JDP, de Oliveira TGL, de Souza-Motta CM, Magalhães OMC, Bundhun D, Harishchandra D, Manawasinghe IS, Dong W, Zhang SN, Bao DF, Samarakoon MC, Pem D, Karunarathna A, Lin CG, Yang J, Perera RH, Kumar V, Huang SK, Dayarathne MC, Ekanayaka AH, Jayasiri SC, Xiao Y, Konta S, Niskanen T, Liimatainen K, Dai YC, Ji XH, Tian XM, Mešić A, Singh SK, Phutthacharoen K, Cai L, Sorvongxay T, Thiyagaraja V, Norphanphoun C, Chaiwan N, Lu YZ, Jiang HB, Zhang JF, Abeywickrama PD, Aluthmuhandiram JVS, Brahmanage RS, Zeng M, Chethana T, Wei D, Réblová M, Fournier J, Nekvindová J, do Nascimento Barbosa R, dos Santos JEF, de Oliveira NT, Li GJ, Ertz D, Shang QJ, Phillips AJL, Kuo CH, Camporesi E, Bulgakov TS, Lumyong S, Jones EBG, Chomnunti P, Gentekaki E, Bungartz F, Zeng XY, Fryar S, Tkalčec Z, Liang J, Li G, Wen TC, Singh PN, Gafforov Y, Promputtha I, Yasanthika E, Goonasekara ID, Zhao RL, Zhao Q, Kirk PM, Liu JK, Yan J, Mortimer PE, Xu J, Doilom M (2019) Fungal diversity notes 1036–1150: taxonomic and phylogenetic contributions on genera and species of fungal taxa. Fungal Divers 96:1–242
Hyde KD, Wong SW (1999) Tropical Australian freshwater fungi. XV. The ascomycete genus Jahnula, with five new species and one new combination. Nova Hedwigia 68:489–510
Entry by
Wei Dong, Faculty of Agriculture and Food, Kunming University of Science and Technology, Kunming 650500, China, Department of Entomology and Plant Pathology, Faculty of Agriculture, Chiang Mai University, Chiang Mai 50200, Thailand, Innovative Agriculture Research Center, Faculty of Agriculture, Chiang Mai University, Chiang Mai 50200, Thailand, Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai 57100, Thailand, Institute of Plant Health, Zhongkai University of Agriculture and Engineering, Haizhu District, Guangzhou 510225, China
Published online 21 May 2026
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