Brachysporium sinense H.W. Shen, K.D. Hyde & Z.L. Luo, 2024

Brachysporium sinense H.W. Shen, K.D. Hyde & Z.L. Luo , sp. nov. FIGURE 2 View FIGURE 2

Fungal Names number: FN 572011; Facesoffungi number: FoF 16614

Etymology: “sinense ” refers to China, where the species was collected.

Holotype: HKAS 131710 View Materials

Saprobic on submerged decaying wood in the freshwater lake. Asexual morph: Colonies on natural substrate superficial, effuse, brown to dark brown, hairy, solitary or gregarious, with glistening conidia at the apex. Mycelium mostly immersed, composed of septate, branch, subhyaline to brown, smooth-walled hyphae. Conidiophores (118–)132–179(–200) µm (x = 156 µm, n = 25) long, 5–7 µm wide at the base, 3.7–4.6 µm wide at the apex, macronematous, mononematous, solitary, erect, straight or slightly flexuous, unbranched, cylindrical, swollen at the base, tapering at the top, septate, pale brown to dark brown, smooth-walled. Conidiogenous cells (20–)28–47(–63) × 4–5 µm (x = 38 × 4.6 µm, n = 25), monoblastic, integrated, terminal, subcylindrical, subhyaline to pale brown, smooth-walled, with one denticle; denticles cylindrical, flexuous, subhyaline, smooth-walled, 9–12.5 × 1.8–2.5 µm. Conidia (22–)32–44(–47) × 21–25 µm (x = 38 × 23 µm, n = 20), acrogenous, solitary, dry, fusoid to limoniform, verrucose, 4-septate, central cells brown to dark brown, polar cells small, subhyaline, smooth-walled. Sexual morph: Undetermined.

Culture characteristics: Conidia germinating on PDA medium and germ tube produced from base of conidium within 12 h. Colonies on PDA medium reaching 2-2.5 cm diam. after two months at room temperature (around 25 °C) in dark, circular, flocculent, dense, brown to dark brown on the forward; circular, dark brown, dense, smooth-edged on the reverse.

Material examined: CHINA, Yunnan Province, Pu’er City, Dujuanhu Lake, 24°32′22.76 N, 101°1′6.85″ E, on submerged decaying wood, 24 February 2023, H.W. Shen, L2132 (KUN-HKAS 131710, holotype), ex-type culture, KUNCC 23-14333.

Notes: Phylogenetic analysis showed that Brachysporium sinense clustered sister to B. polyseptatum within Brachysporium with low support ( FIGURE 1 View FIGURE 1 ). Brachysporium sinense very resembles B. pendulisporum in having holoblastic, terminal, denticulate, hyaline conidiogenous cells, and fusoid to limoniform, verrucose, septate conidia with brown to dark brown central cells and subhyaline, small polar cells. However, the conidiogenous cell of B. sinense are monoblastic, with a single denticle developing on the apex, whereas the conidiogenous cell of B. pendulisporum are polyblastic, with one or more denticles ( Hughes 1955; Réblová & Seifert 2004; Markovskaja & Treigiené 2007). In addition, B sinense has longer and wider conidia (32–44 × 21–25 µm vs. 32.5–35.5 × 14.5–16.2 µm) than B. pendulisporum ( Hughes 1955) . Brachysporium sinense is distinguished from B. polyseptatum by having a polyblastic conidiogenous cells, and long-obovoid, larger conidia (22.6–30 × 9.7–12 µm vs. 32–44 × 21–25 µm) ( Hughes 1955). According to the guidelines proposed by Chethana et al. (2021), based on the unique morphological and phylogenetic evidence, we introduce B sinense here as a new species from a lentic freshwater habitat.