Fungalpedia – Note 2881, Isthmoconidium
Isthmoconidium Etayo & Fr. Berger.
Citation when using this data: Meng QF et al. – Fungalpedia.
Index Fungorum, Faceoffungi, MycoBank, GenBank Fig 1.
Classification: Ascomycota genera incertae sedis, Fungi.
Isthmoconidium was introduced by Etayo et al. (2013a) to describe the type species I. bacidiicola, which grows on the thalli of the corticolous lichen Bacidia heterochroa. The genus is characterized by black, punctiform conidiomata that are initially immersed with a pycnidioid or pseudocupulate appearance, later becoming slightly erumpent. The conidiophores are hyaline to violaceous, irregularly branched, and multiseptate. Conidia are violaceous-brown, comprising 2 (rarely 3 or 4) inflated cells connected by a thin isthmus, and are smooth-walled (Etayo et al. 2013a). Due to the lack of molecular data, Isthmoconidium has been tentatively placed within Ascomycota genera incertae sedis (Hyde et al. 2024). Further phylogenetic studies are needed to clarify its systematic position.
Type species: Isthmoconidium bacidiicola Etayo & F. Berger (Etayo et al. 2013a).
Figure 1 – Isthmoconidium bacidiicola redrawn from Etayo et al. (2013a). a The black sporodochia on the thallus of the host, Bacidia heterochroa. b Vertical section through a partially immersed sporodochium. c Conidiophores with conidiogenous cells and 2-celled conidia. Scale bars: a = 200 μm, b = 20 μm, c = 10 μm.
References
Entry by
Meng QF, Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai, 57100, Thailand and School of Public Health, Zunyi Medical University, Guizhou 563000, China.
Published online 24 July 2026