Myrmecridium Arzanlou, W. Gams & Crous, Stud. Mycol.58: 84 (2007)
MycoBank number: MB 504559; Index Fungorum number: IF 504559; Facesoffungi number: FoF 07925; 13 species with sequence data.
Type species – Myrmecridium schulzeri (Sacc.) Arzanlou, W. Gams & Crous
Notes – Myrmecridium accommodates ramichloridium-like taxa with hyaline mycelium and pale brown to hyaline, conidiogenous cells with pimple-like denticles. Among the 15 epithets listed in Index Fungorum (2020), M. montsegurinum is reported as a sexual morph in Myrmecridium (Réblová et al. 2016a) and the remaining 14 taxa are based on their asexual morphs. Because Myrmecridium sorbicola has septate conidia and it phylogenetically groups with species of Neomyrmecridium, it was transferred to the latter genus (Crous et al. 2018b).
Myrmecridium montsegurinum, which is the only known sexual morph in Myrmecridium, occurs on decaying wood of various deciduous trees submerged in freshwater (Réblová et al. 2016a). Myrmecridium montsegurinum shares a close phylogenetic affinity to M. schulzeri and M. flexuosum, but statistical support for this alliance is not significant (Réblová et al. 2016a).
Figure 167 – Myrmecridium montsegurinum (Material examined – FRANCE, Midi-Pyrénées: Ariège, Montségur, Le Lasset stream along D9 road, 880−890 m a.s.l., on submerged wood of Fraxinus excelsior, 1 October 2013, J. Fournier J.F. 13180, PRM 934684, holotype). a Specimen label and host. b, c Appearance of stromata on substrate. d-f Vertical section of ascostroma. g Ostiolar canal. h Peridium. i, j Asci and paraphyses. k-o Asci with ascospores (k = stained with lugo’s iodine). p-s Ascospores. Scale bars: d = 150 µm, e = 100 µm, g, i, k = 50 µm, j, l-o = 30 µm, h = 25 µm, p-s = 10 µm
Figure 168 – Myrmecridium schulzeri (CBS 325.74) (a, b, c, e), M. ﬂexuosum (CBS 398.76) (d), M. sorbicola (CBS 143433) (f), M. iridis Crous (CBS 139917) (g). a-d Conidiophores. e-g Conidia (Redrawn from Arzanlou et al. 2007, Crous et al. 2015c, 2018c). Scale bars: a = 100 µm, b-g = 10 µm.