Chaetoconis polygoni (Ellis & Everh.) Clem., Gen. fung.: 176 (1909)
Saprobic on stem of Rumex acetosa (Polygonaceae). Sexual morph: undetermined. Asexual morph: Conidiomata 200–250 µm diam., 100–150 µm high, dark brown to black, pycnidial, solitary to gregarious or confluent, deeply immersed at beginning, then becoming partly erumpent, globose, unilocular or multilocular, thick-walled, glabrous, ostiolate. Ostiole 50–70 × 50–60 µm, single, cylindrical to subcylindrical, centrally located. Conidiomata wall 20–45 µm wide, composed of thick-walled, dark brown cells of textura angularis in the outer layer, thin-walled, pale brown cells of textura prismatica in the inner layer. Conidiophores 4–10 × 3–9 µm, formed from the innermost cells of conidiomata, hyaline, broadly cylindrical or irregular, septate, branched, smooth-walled, invested by mucus. Conidiogenous cells 8–17 × 2–8 µm, enteroblastic, phialidic, hyaline, subcylindrical to cylindrical or irregular, straight or curved, discrete or mostly integrated, with marked periclinal thickenings in the collarette zone. Conidia 33–48 × 2.5–5 µm (x= 40 × 4 µm; n = 30), hyaline, obclavate, with obtuse or slightly truncate base, 2-septate, guttulate, central cell generally shorter than end cells, apical cell attenuated into a tubular, flexuous, unbranched appendage 18–37 × 1–2 µm.
Material examined: Germany, on the edge of a mixed forest, 39 m asl, sandy, acid, fresh, mesotroph, on stem of Rumex acetosa (Polygonaceae), 9 May 2013, R.K. Schumacher, CHUNI 73 (MFLU 17-0965).
Chaetoconis polygoni (MFLU 17–0965) a Herbarium specimen. b, c, d Appearance of black conidiomata on the host. e, f Vertical sections of conidiomata. g Section of peridium. h Ostiole. i–l Conidiophores, conidiogenous cells and developing conidia. m–s Conidia. Scale bars b = 1000 µm, c–d = 200 µm, e–f = 100 µm, g = 50 µm, h = 20 µm, i = 5 µm, j–s= 10 µm.
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.