Addition to Pseudoplagiostomataceae: Pseudoplagiostoma inthanonense sp. nov. from Doi Inthanon National Park, Northern Thailand Author Hittanadurage Silva, Veenavee S. 0000-0001-8921-1370 School of Science, Mae Fah Luang University, Chiang Rai, 57100, Thailand & Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai, 57100, Thailand & sulakkanaveenavee @ gmail. com; https: // orcid. org / 0000 - 0001 - 8921 - 1370 sulakkanaveenavee@gmail.com Author Perera, Rekhani H. 0000-0002-1360-5362 Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai, 57100, Thailand & School of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul, 08826, Republic of Korea & hansi. rekha 2 @ gmail. com; https: // orcid. org / 0000 - 0002 - 1360 - 5362 hansi.rekha2@gmail.com Author Gomes De Farias, Antonio R. 0000-0003-4768-1547 School of Science, Mae Fah Luang University, Chiang Rai, 57100, Thailand & Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai, 57100, Thailand & rfariasagro @ gmail. com; https: // orcid. org / 0000 - 0003 - 4768 - 1547 rfariasagro@gmail.com text Phytotaxa 2023 2023-11-07 625 1 66 76 https://phytotaxa.mapress.com/pt/article/download/phytotaxa.625.1.4/51269 journal article 278553 10.11646/phytotaxa.625.1.4 79dd5ec5-27d2-4ae3-923e-9d50106ee31a 1179-3163 10151712 Pseudoplagiostoma inthanonense V. S. Hittanadurage Silva, R.H. Perera, and Gomes de Farias , sp. nov. Figure 2 Index Fungorum Number : IF 901198 Faces of Fungi : FoF 15022 Etymology— inthanonense derived from “Doi Inthanon”, a National Park Reserve in northern Thailand where the specimens were collected. Holotype — MFLU 23-0345 Saprobic on broadleaf species leaf litter. Sexual morph: Undetermined. Asexual morph: Coelomycetous. Conidiomata: 80–140 µm height, 70–120 µm diameter (x̅ = 103 × 109 µm, n = 5), pycnidial, exuded conidia as pale-yellow drops, solitary, immersed, globose to subglobose, moderate to dark brown, emerging through the plant tissue. Conidiomata walls: 5–10 µm wide, comprising 2–3 layers of thin-walled, yellowish brown, pseudoparenchymatous cells, forming textura angularis and intermixed with the host cells at the base and sides. Paraphyses: 0.9–2 µm wide, branched, septate, hyaline. Conidiophores: reduced to conidiogenous cells; Conidiogenous cells 3.3–12.3 × 1–2.7 µm (x̅ = 7 × 1.7 µm, n = 25), arising from the inner cell layer, phialidic, cylindrical to lageniform, hyaline, smooth-walled. Conidia: 14–22.6 × 6.4–10.2 µm (x̅ = 17.5 –8.5 µm, n = 60), mainly ellipsoid, oblong, oval, reniform or pyriform, aseptate, with an obtuse apex and protruding scar at the tapering base, straight or slightly curved, guttulate, hyaline, thick-, smooth-walled ( Figure 2 ). FIGURE 2. Pseudoplagiostoma inthanonense . (MFLU 23-0345, holotype). a = Host substrate. b, c = Pycnidia with conidial exudates. d = Cross section of the conidioma. e = Conidiomata wall. f = Paraphyses. g–k = Conidiogenous cells with attached conidia. l–p = Conidia. q = Germinated conidium. r = Culture in PDA media. s = Culture in MEA media. t = Spore masses on cultures in MEA media. Scale bars: d–f, q = 20 µm, g–p = 10 µm. Culture characteristics : Colonies on MEA reaching 22 mm diam. after 4 days at 20–25 °C, above white, becoming whitish grey when mature, reverse white with yellowish green center reaching charcoal grey center with creamy colour margins, mycelium medium spares to medium when mature, sporulated after 30 days, spore exudate, circular, effuse to raised, entire, velvety, slightly irregular margin, not producing pigmentation. Colonies on PDA reaching 19 mm diam. after 102 days at 20–25 °C, above white, reaching whitish grey when mature, reverse yellowish grey, medium, convex, lobate margin, wrinkled folded. Material exsamined: Thailand , Chiang Mai Province , Doi Inthanon National Park Reserve , Huai Sai Lueang Waterfall area , on a leaf of diseased unknown broadleaf species, 30 November 2022 , V. S. Hittanadurage Silva , V049, holotype MFLU 23-0345 , ex-type living culture MFULCC 23-0262 . GenBank accession numbers: ITS: OR606510 ; LSU: OR633320 ; tef1α : OR650831 ; tub2 : OR611920 ; rpb2 : OR611921 Notes— Pseudoplagiostoma inthanonense is phylogenetically related to P. mangiferae ( Figure 1 ). The holotype of P. mangiferae was collected from a living leaf of Mangifera in China ( Phookamsak et al. 2019 ). However, P. inthanonense is distinguished by possessing smaller conidia and conidiogenous cell sizes. Furthermore, the shape of P. inthanonense conidiogenous cells differs from that of P. mangiferae , displaying a cylindrical to lageniform. Compared to P. dipterocarpicola , described in Thailand , P. inthanonense exhibits larger spore size and wider conidiogenous cells ( Tang et al. 2022 ). A comprehensive comparison of values is presented in Table 4 . The pairwise sequence comparisons showed that P. inthanonense is distinguished from P. mangiferae by 18/520 bp (3.46%, gaps two bp) in ITS , 3/778 (0.38 %, gap zero pb) in LSU and 39/439 (8.88%, gap two bp) in tub2 . Therefore, based on the morphological, phylogenetic, and molecular evidence, we introduce P. inthanonense as a new species.