Sigarispora clavata D.F. Bao, Z.L. Luo, K.D. Hyde & H.Y. Su
Index Fungorum number: IF 556722; Facesoffungi number: FoF06214
Holotype: MFLU 19–0994
Etymology: Referring to the clavate ascospores
Saprobic on submerged decaying wood in freshwater habitats. Sexual morph: Ascomata 327– 470μm high, 280–460μm diam ( = 380 × 400 μm, n = 5), semi-immersed to immersed, subglobose, coriaceous, black, ostiolate. Ostiole slit-like, variable in shape, with a crest-like apex and a pore-like opening, plugged by gelatinous tissue, made up of lightly pigmented, pseudoparenchymatous cells. Peridium 32–55 μm wide, comprises a single stratum, with brown to dark brown cells of textura globulosa and textura angularis. Hamathecium comprising 1.5–2 μm wide, filiform, hyaline, septate, guttulate, smooth cellular pseudoparaphyses. Asci 91–117 × 9–12 μm ( = 104 × 11 μm, n = 20), cylindrical, round at the apex, bitunicate, long pedicellate, with a small ocular chamber at the apex. Ascospores 13–17 × 4–6 μm ( = 15.4 × 5.3 μm, n = 30), uni to bi-seriate, overlapping, ellipsoidal to clavate, with obtuse ends, straight or slightly curved, hyaline when young, dark brown to yellowish brown at maturity, 1–4-septate, slightly constricted at the septum, guttules, smooth walled. Asexual morph: Undetermined. (Descriptions from Bao et al. 2019)
Material examined: CHINA, Tibet Autonomous Region (30°15'08.02" N, 82°58'27.77" E), on submerged decaying wood, May 2017, Z.L. Luo, 2XZ A 1–2–1, S-1483 (MFLU 19–0994, holotype), ex-type culture, MFLUCC 18–1316.
Notes: Species of Sigarispora are characterized by immersed, papillate, ostiolate ascomata, a peridium of pseudoparenchymatous cells, bitunicate, fissitunicate asci and ellipsoidal-fusiform or muriform ascospores, with or without sheaths, and appendages. Species fits well within the species concept of genus Sigarispora. However, species can be distinguished from other species of Sigarispora by its 1–4-septate, ellipsoidal to clavate ascospores with obtuse ends.
Sigarispora clavata shares similar morphological characteristics with S. caudata in having immersed to semi-immersed, coriaceous ascomata, bitunicate, cylindrical asci with ocular chamber and brown to dark brown ascospores. However, S. clavata differs from S. caudata in ascomatal size (380–400 × 280–460 vs. 145–210 × 210–305 μm) and ascospores shape, septations and size (1–4 vs. 4–6 septate, 13–17 × 4–6 vs. 23.5–34.5 × 5.5–7 μm, respectively), S. clavata has ellipsoidal to clavate ascospores with obtuse ends, whereas ascospores of S. caudata are fusiform with narrow and acute ends.