Pseudohalonectria lutea Shearer, Can. J. Bot. 67(7): 1950 (1989)
Index Fungorum number: IF 136213; Fig. 1
Saprobic on decaying wood submerged in a river. Sexual morph: Ascomata 300–550 × 300–599 μm, solitary to less commonly aggregated, immersed, globose to depressed globose, with a long neck, greenish yellow brown, gradually becoming dark near the base, rostrate. Neck cylindrical to conical, composed of parallel hyphae, greenish yellow at above, dark brown to black at base, periphysate. Peridium membranous, comprising 5–10 layers, inner layers composed of pale yellow cells of textura angularis, outer layer composed of darkened yellow compressed cells of textura angularis. Paraphyses 4–6 μm wide, numerous, septate, hyaline, smooth. Asci 128–188 × 16.1–23.7 μm (x̅ = 151 × 20.2 μm, n = 20), 8-spored, unitunicate, cylindrical, short pedicellate, with thimble-shaped ascus ring, separating from ascogenous hyphae. Ascospores 46–59 × 6.4–9 μm (x̅ = 54 × 7.5 μm, n = 20), overlapping 2–3-seriate, hyaline to pale orange in mass, end cells less pigmented than inner cells, long ellipsoidal, 5-septate, slightly constricted at septa smooth-walled.
Material examined: CHINA, Tibet Autonomous Region, on submerged decaying wood, 28 April 2015, Z.L. Luo, XZ A 2–2–1, S-1048, MFLU 18–1463; living culture, MFLUCC 18–1297.
GenBank numbers: LSU: MK063809, SSU: MK063810, tef1: MK099812.
Notes: Our new isolate fits well with the original description of P. lutea. However, in the phylogenetic analysis, our new isolate (MFLUCC 18–1297), P. lutea (CBS 126574) and P. lignicola clustered together. However, Pseudohalonectria lutea differs from the P. lutea type in having larger asci (122–192 × 14.4–18 vs 90–132 × 11–17.6 μm) and ascospores (48–68 × 4.8–8.4 vs 38.4–74.8 × 3.6–6.6 μm), Moreover, P. lutea is characterized by ellipsoidal, 5-septate ascospores, while in P. lignicola ascospores are 5–11-septate and cylindrical (Shearer 1989). Perera et al. (2016a) discussed the problem of P. lutea and P. lignicola sequences submitted to GenBank. According to our findings, our species is similar to P. lutea and therefore we identified our isolate as P. lutea. This species group, which is probably a species complex needs resolving.
Fig. 1: Pseudohalonectria lutea (material examined: CHINA, Tibet Autonomous Region, on submerged decaying wood, 28 April 2015, Z.L. Luo, XZ A 2–2–1, S-1048, MFLU 18–1463; living culture, MFLUCC 18–1297). a, b. Ascomata necks on decaying wood. c, d. Sections of ascomata. e. Peridium. f-h. Asci. i Paraphyses. j. Ascal apical ring in side view. k-m. Ascospores. n. Germinating ascospore. o, p. Culture on PDA. Scale bars: c, d = 150 μm, e, i, j, n = 20 μm, f, g = 40 μm, i = 45 μm, k-m = 25 μm.