Phaeoisaria motuoensis K. Xu, R.J. Xu & Y.A. Zhu

Xu, Ke, Xu, Rong-Ju, Li, Jia-Ning, Zhao, Qi & Zhu, Ying-An, 2024, A novel species of Phaeoisaria (Pleurotheciaceae, Sordariomycetes) from the Tibetan Plateau, China, Phytotaxa 642 (1), pp. 61-72 : 67

Phaeoisaria motuoensis K. Xu, R.J. Xu & Y.A. Zhu , sp. nov. FIGURE 3

Index Fungorum number: 900235, Facesoffungi number: FoF 14354

Etymology: The species epithet refers to Motuo County, where the holotype was collected.

Holotype: HKAS 128729

Saprobic on decaying submerged wood in a freshwater stream. Asexual morph: Colonies effuse, scattered, solitary, pale brown to dark brown, hairy or velvety, covered by white conidial mass. Mycelium is partly superficial, partly immersed in the substrate, consisting of branched, septate, smooth, subhyaline to pale brown hyphae. Synnemata 550–1290 × 13–35 μm (x = 730 × 20 μm, n = 10), macronematous, branched, synnematous, septate, straight or slightly flexuous, brown to dark brown, smooth. Conidiogenous cells 20–25 × 2–4 μm (x = 23 × 3 μm, n = 10), polyblastic, hyaline to pale brown, integrated, sympodial, terminal, cylindrical, ellipsoidal or subulate, denticulate. Conidia 6–10 × 3–6 μm (x = 8 × 4 μm, n = 20), ellipsoidal to obovoid, hyaline to pale brown, guttulate, smooth-walled, aseptate. Sexual morph: Undetermined.

Culture characteristics: Conidia germinated on PDA within 48 hours, and germ tubes were produced from both ends. Colony reached 27 mm at room temperature for 4 weeks, circular, flat, with fluffy, dense, dark brown mycelium in the center, celadon to grey from above, atrovirens from below, becoming sparse and paler or light brown at the entire margin, edge entire.

Material examined: CHINA, Xizang, Motuo County, saprobic on decaying submerged wood in a freshwater stream, 13 July 2022, K. Xu, XK-34 ( HKAS 128729, holotype), ex-type living culture, KUNCC 10410. Motuo County, saprobic on decaying submerged wood in a freshwater stream, 15 July 2022, K. Xu, XK-34-8 ( HKAS 128730), living culture, KUNCC 10450.

Notes: Phaeoisaria motuoensis forms a distinct clade sister to P. sedimenticola . Morphologically, P. motuoensis is similar to P. sedimenticola in having terminal, smooth, denticulate, hyaline to pale brown conidiogenous cells and ellipsoidal to obovoid, straight, hyaline, guttulate, smooth-walled conidia. However, P. motuoensis clearly differs from P. sedimenticola by having shorter synnemata (547–1289 μm vs. up to 4000 μm), and conidia (aseptate vs. 1-septate) ( Cheng et al. 2014).

Figures

FIGURE 3. Phaeoisaria motuoensis (HKAS 128729 holotype). a Colony on a natural substrate. b, c Conidiophore and Conidiogenous cell. d, e Conidiogenous cell and conidiophore. f–h Conidiogenous cell with developing conidia. i–n Conidia. o Colony on PDA. Scale bars: a = 200 μm, b–c = 100 μm, d–e = 20 μm, f–n = 10 μm.