Rubellisphaeria abscondita Réblová & J. Fourn.
Etymology: Absconditus (L), meaning hidden, concealed, referring to ascomata immersed in the decaying wood.
Sexual morph: Ascomata solitary or in small groups, immersed, gradually erumpent to semi-immersed, venter globose to subglobose, subhyaline to reddish brown, rarely dark brown, 280−300 μm diam, 240−290 μm high, glabrous. Necks usually laterally curved upwards, rarely central, 80−90 μm diam, 100−150 (200) μm long, cylindrical, dark brown, sometimes red or red-brown at the apex. Ostiole periphysate. Ascomatal wall 15−25 μm thick, leathery to waxy, two-layered. Outer layer consisting of subhyaline to reddish brown cells of textura prismatica, towards the interior grading into several layers of thin-walled subhyaline, flattened cells. Paraphyses hyaline, septate, slightly constricted at the septa, cylindrical, 5.0−6.5 μm wide, tapering, longer than the asci. Asci (105)113−126(130) × 9.0−11(12) μm (mean ± SD =117.6 ± 1.4 × 10.6 ± 0.3 μm), in the sporiferous part 97−107 μm (mean ± SD = 101.3 ± 1.3 μm) long, short-stipitate, cylindrical, apex obtuse, with a non-amyloid apical annulus c. 3.5 μm diam, 2.5 μm high. Ascospores 14.5−16.5(17) × 6.0−7.5 μm (mean ± SD =15.5 ± 0.2 × 6.7 ± 0.1 μm), ellipsoidal, slightly inequilateral, non-septate, with delayed formation of a middle septum, smooth-walled, thin-walled, hyaline, obliquely uniseriate in the ascus. Asexual morph: Undetermined.
Characters in culture: Colonies on PDA reaching a radius of 8–15 mm after 30 d at 25 °C in darkness, circular, flat, with entire margins, felty. Colony surface pale brown towards the margin, reverse brown. Sporulation absent.
Specimens examined: France, Loire: Saint Jean la Vêtre, Les Yverneaux, 1080 m a. s. l., on submerged twigs of Abies alba in a peat bog, leg. J. Fournier J.F. 10029, 4. 5. 2010. Holotype (PRM 934681), ex-type culture (CBS 132078). Ibid., J.F. 10028 (PRM 934682), J.F. 10030 (PRM 934683).
Habitat: On submerged coniferous wood in a stream, France. Known only from the type locality.
Notes: Rubellisphaeria is closely related to Atractospora from which it differs by more oblique, globose to subglobose, immersed to semi-immersed ascomata with subhyaline to reddish brown wall and ellipsoidal ascospores with a delayed formation of the middle septum (Réblová et al. 2016). It formed a well-supported clade with Atractospora in the phylogenetic analyses of, Luo et al. (2019) and Hyde et al. (2020).
Hyde KD, Norphanphoun C, Maharachchikumbura SSN, Bhat DJ et al. 2020 – Refined families of Sordariomycetes. Mycosphere 11(1): 305–1059.Luo ZL, Hyde KD, Liu JK, Maharachchikumbura SSN et al. 2019 – Freshwater Sordariomycetes. Fungal Diversity 99, 451–660.
Luo ZL, Hyde KD, Liu JK, Maharachchikumbura SSN et al. 2019 – Freshwater Sordariomycetes. Fungal Diversity 99, 451–660.
Réblová M, Fournier J, Štěpánek V. 2016 - Two new lineages of aquatic ascomycetes: Atractospora gen. nov. and Rubellisphaeria gen. et sp. nov., and a sexual morph of Myrmecridium montsegurinum sp. nov. Mycol Progress (2016) 15: 21.