Pleosporales » Pleosporales genera incertae sedis » Isthmosporella

Isthmosporella pulchra

Isthmosporella pulchra Shearer & Crane

Index Fungorum number: IF 450566

Etymology: Latin feminine of pulcher = beautiful

Holotype: ILLS 53086.

 

Sexual morph: Ascomata scattered on decorticated wood, immersed obliquely, becoming erumpent to superficial, globose, black, membranous, glabrous, rostrate, 310–330 × 225–240 μm. Ascomal wall 2-layered, inner layer composed of 5–7 rows of fusoid, subhyaline to light brown, compressed cells, 11–20 × 2–3.5 μm; outer 3–4 cell layers composed of brown, pseudoparenchymatic, fusoid-cylindric cells, 2–6.5 μm long. Beak short, cylindrical, periphysate, 60 μm long, 55 μm wide. Hamathecium sparse, of broad, septate, interascal pseudoparaphyses. Asci in a broad basal layer, fissitunicate, ventricose to clavate, broadly rounded at apex, shortstalked, 8-spored, persistent, (95–)135–160(–175) × (25–)30–45(–60) μm. Ascospores tri- to tetraseriate, hyaline, filled with lipid droplets that merge to form large guttules, cylindrical to fusoid, isthmoid at center, sometimes bent at isthmus and becoming u- or v shaped, end cells tapering, 12–17-phragmoseptate, constricted at septa, 80–105(–110) × (7–)8–10 μm wide; isthmus 1-septate, 2–5.5 × 2.0–4.5 μm, frequently fragmenting to form part spores; surrounded by a gelatinous sheath with a dense region near the isthmus, sheath greatly enlarging in water. Asexual morph: Undetermined (Descriptions from Shearer & Crane 1999).

 

Material examined: USA. New York: Adirondack Park. Piercefield. Tupper Lake at public boat launch from Rt. 30, UTM Zone 18, 539840mE, 4892100mN; 44°10'59"N, 80°31'6''W, on submerged, decorticated wood, 7 Jul 1994, JL. Crane & CA. Shearer A-254-1, ILLS 53086.

 

Freshwater distribution: USA (Shearer and Crane 1999)

 

Fig 1. Isthmosporella pulchra (Material examined: USA, New York, Adirondack Park, Piercefield, Tupper Lake at public boat launch from Rt. 30, UTM Zone 18, on submerged, decorticated wood, A254-2). a Squash mount of ascoma. b Bitunicate ascus. c, d Ectotunica rupturing at the apex and becoming strongly wrinkled and curled inwards. e Pseudoparaphyses. f, h Ascospores. Note gelatinous sheath with a dense region near the isthmus (arrowed in f). g. Ascospore in glycerin. Scale bars: a = 100 µm, b–h = 20 µm (Dong et al. 2020)

 

References

Dong W, Wang B, Hyde KD, McKenzie EHC, Raja HA, Tanaka K, Abdel-Wahab MA, Abdel-Aziz FA, Doilom M, Phookamsak R, Hongsanan S, Wanasinghe DN, Yu X-D, Wang G-N, Yang H, Yang J, Thambugala KM, Tian Q, Luo Z-L, Yang J-B, Miller AN, Fournier J, Boonmee S, Hu D-M, Nalumpang S, Zhang H (2020) Freshwater Dothideomycetes. Fungal Divers 105:319–575

Shearer CA, Crane JL (1999) Freshwater Ascomycetes: Isthmosporella pulchra gen. et sp. Mycologia 91:141–144

 

Recent Genus

1
Neochlamydotubeufia
Neohelicomyces

Recent Species

Neohelicomyces submersus
Neohelicomyces hyalosporus
Neohelicomyces grandisporus