Fungalpedia – Note 1582, Myriellina
Myriellina Höhn.
Index Fungorum, Facesoffungi, MycoBank, GenBank, Fig 1
Classification: Incertae sedis, Incertae sedis, Incertae sedis, Incertae sedis, Pezizomycotina, Ascomycota, Fungi
Habit on leaves of Cydonia vulgaris (Rosaceae), Imperata cylindrica (Poaceae). Sexual morph: undetermined. Asexual morph: Conidiomata brown, acervular, solitary, subepidermal, immersed to erumpent, linear in outline, subglobose in section view, unilocular, glabrous. Ostiole indistinct, dehiscence by irregular rupture of the apical wall. Conidiomatal wall composed of thin-walled, pale brown cells of textura angularis extending into the hypodermis. Conidiophores arising from the inner cell layers of basal stroma, hyaline, cylindrical, simple or branched, septate, smooth-walled. Conidiogenous cells hyaline, enteroblastic, phialidic, cylindrical to lageniform or irregular, integrated or discrete, determinate, smooth-walled. Conidia hyaline, cylindrical to fusiform, tapered towards apex, truncate at the base, 1–5-septate (mostly 3-septate), smooth-walled.
Notes: Sutton (1980) re-described Myriellina and provided a detailed description for the genus. Sankaran and Sutton (1991) described the second species M. imperatae B. Sutton & Sankaran from Imperata cylindrica (Poaceae) in Australia. Myriellina imperatae differs from M. cydoniae by its larger conidia; (15.5–)22–40.5 × 1.5–2 µm in M. imperatae, and 9–17 × 2.5–3 µm in M. cydoniae (Sutton 1980, Sankaran and Sutton 1991). Both Myriellina species are associated with leaf lesions (Sutton 1980, Sankaran and Sutton 1991).
Myriellina is similar to Cheilaria in having acervular conidiomata and fusiform, septate conidia. The differences between those two genera are basal stroma and conidial septation. Cheilaria has basal stroma composed of rather thick-walled, dark brown to pale brown cells of textura angularis to textura epidermoidea, and 0–3-septate (usually 2-septate) conidia. Myriellina has basal stroma composed of thin-walled, pale brown cells of textura angularis, and 1–5-septate (usually 3-septate) conidia. However, conidial septation is not a sufficient character for generic delineation (Minnis et al. 2012). Thus, Cheilaria and Myriellina might be taxonomically congeneric. The differences of basal stroma between these two genera can be used to delineate taxa at the species level. There is no molecular data available for Cheilaria or Myriellina. Therefore, fresh collections are needed to verify our hypothesis.
Type species: Myriellina cydoniae (Desm.) Höhn., Sber. Akad. Wiss. Wien, Math.-naturw. Kl., Abt. 1 124: 100 (1915).
Other accepted species: Species Fungorum – search Myriellina.
Figure 1 – Myriellina cydoniae (redrawn from Sutton 1980) a Conidiophores, conidiogenous cells and developing conidia. b Conidia. c Vertical section of conidioma.
References
Li WJ, McKenZie EHC, Liu JK, Bhat DJ, Dai DQ, Caporesi E, Tian Q, Maharachcikumbura SSN, Luo ZL, Shang QJ, Zhang JF, Tangthirasunun N, Karunarathna SC, Xu JC, Hyde KD 2020 – Taxonomy and phylogeny of hyaline-spored coelomycetes. Fungal Diversity 100: pages279–801.