Atractosporales » Atractosporaceae » Rubellisphaeria

Rubellisphaeria abscondita

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.