Fungalpedia – Note 2578, Mixtoconidium
Mixtoconidium Etayo
Citation when using this data: Meng QF et al. – Fungalpedia.
Index Fungorum, Facesoffungi, MycoBank, GenBank, Fig 1, 2.
Classification: Lecanographaceae, Arthoniales, Arthoniomycetes, Pezizomycotina, Ascomycota, Fungi
Mixtoconidium was first established by Etayo (1995b) to describe the type species M. canariense, discovered on Ramalina canariensis. Etayo suggested that M. canariense might be identical to the asexual morph of Celidium insidens, a fungus associated with Ramalina fraxinea. The following year, Etayo (1996b) described the sexual morph of Mixtoconidium from additional samples. Since M. canariense was initially based solely on its asexual morph, van den Boom et al. (2017a) designated M. insidens as the neotype, as it exhibits both morphs. Additionally, two new combinations were described: Mixtoconidium insidens (previously known as Celidium insidens), which occurs on Ramalina fraxinea, and Mixtoconidium nashi (previously Plectocarpon nashi), found on the thallus of Niebla robusta.
The asexual morph of Mixtoconidium is characterized by subglobose, dark brown to black conidiomata; subcylindrical or obclavate hyaline conidiogenous cells; and hyaline, cylindrical or allantoid macroconidia with a single septum that are either straight or slightly curved. Additionally, it produces bacilliform, non-septate microconidia (Etayo 1995a). The sexual morph features flat to convex, dark brown ascomata covered with orange pruina, clavate asci containing eight spores each, and brownish ascospores with three septa surrounded by a halo (van den Boom et al. 2017a).
Diederich et al. (2018a) placed Mixtoconidium within Arthoniales genera incertae sedis. Later, Wijayawardene et al. (2020) and Hyde et al. (2024) placed it within Lecanographaceae (Arthoniales). However, the phylogenetic position of Mixtoconidium remains uncertain due to the absence of molecular data.
Type species: Mixtoconidium insidens (Vouaux) Etayo & van den Boom
= Celidium insidens Vouaux
Other accepted species: Species Fungorum – search Mixtoconidium
Figure 1 – Asexual morph of Mixtoconidium insidens redrawn from Etayo (1995a). a Section of conidiomata. b Conidiogenous cells with macroconidia and microconidia. c Septate macroconidia and bacillar microconidia. Scale bars: a = 100 μm, b, c = 10μm.
Figure 2 – Sexual morph of Mixtoconidium insidens redrawn from van den Boom et al. (2017a) & webpage https://fungi.myspecies.info/all-fungi/mixtoconidium-insidens). a Apothecia. b, c Immature ascus with colorless spores or light brown spores. d Mature ascus with brownish spores. Scale bars: a = 1mm, b–d = 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 5 June 2026