Xenoanthostomella chromolaenae Mapook & K.D. Hyde, in Hyde et al., Fungal Diversity 100: 237 (2020)

Index Fungorum number: IF 556908; MycoBank number: MB 556908; Facesoffungi number: FoF 06796

Etymology – Name reflects the host genus Chromolaena, from which this species was isolated.

Holotype – MFLU 20-0048

Saprobic on dead stems of Chromolaena odorata. Sexual morph: Ascomata 190–220 µm high × 175–210 µm diam. (x̄ = 200 × 190 µm, n = 5), immersed beneath clypeus, uni-locular, globose to obpyriform, coriaceous, solitary to scattered. Clypeus extending outwards around the ascomata, thicker around the papilla. Ostiole central, papillate. Peridium 15–25 µm wide, comprising several layers, inner layers comprising hyaline to brown cells of textura epidermoidea, outer layers comprising brown cells of textura intricata at the side with textura angularis at upper part. Paraphyses 2.5–4 µm wide, cylindrical, septate with small guttules, hyaline, branching, and embedded in a gelatinous matrix. Asci 60–98 × 5–7.5 µm (x̄ = 83.5 × 6 µm, n = 25), 8-spored, unitunicate, cylindrical to broadly filiform, pedicellate, straight or slightly curved, with an inconspicuous apical ring. Ascospores 10.5–14 × 4–5.5 µm (x̄ = 12 × 5 µm, n = 20), 1-seriate, hyaline when immature, becoming brown to dark olivaceous- brown when mature, unicellular, inequilateral to broadly fusiform, tapering towards narrow ends, verruculose when immature with 1–2 large guttules when mature. Asexual morph: Undetermined.

Culture characteristics – Ascospores germinating on MEA within 72 h at room temperature and germ tubes produced from both ends. Colonies on MEA irregular, mycelium umbonate and undulate margins, white aerial hyphae at the surface and brown in reverse with white-yellow at the margin. Material examined: THAILAND, Lampang Province, Ngao, on a dead stem of Chromolaena odorata (Asteraceae), 21 September 2016, A. Mapook, LP6 (MFLU 20-0048, holotype), ex-type culture MFLUCC 17-1484.

GenBank  numbers – ITS = MN638863, LSU = MN638848, SSU = MN638852, RPB2 = MN648729, TEF1-α = MN648732.

Notes – In a BLASTn search of NCBI GenBank, the closest match of the ITS sequence of Xenoanthostomella chromolaenae (MFLUCC 17-1484, ex-holotype) is Idriella lunata P.E. Nelson & S. Wilh. with 98.65% similarity to strain MUCL 4103 (KC775734). The closest match of the LSU sequence with 99% similarity was to Circinotrichum papakurae S. Hughes & Piroz. (strain CBS 101373, KR611897). The closest matches of the SSU sequence with 99.09% similarity was to Circinotrichum sinense D.W. Li et al. (strain UAMH11913, KY994108), while the closest matches of the RPB2 sequence with 81.51% similarity was to Camillea tinctor (Berk.) Læssøe, J.D. Rogers & Whalley (strain CBS 203.56, KU684282).

Fig. 1. Xenoanthostomella chromolaenae (MFLU 20-0048, holo- type). a, b Appearance of ascomata on substrate. c Section through of ascoma. d Peridium. e Pseudoparaphyses. fi Asci. jo Ascospores. Scale bars: a, b = 200 µm, fi = 50 µm, c, d, jo = 20 µm, e = 10 µm