Immersisphaeria Jaklitsch, Mycotaxon, 2007

Daranagama, Dinushani A., Liu, Xingzhong, Chamyuang, Sunita, Stadler, Marc, Bahkali, Ali. H. & Hyde, Kevin D., 2016, Towards a natural classification of Sordariomycetes: The genera Frondisphaeria, Immersisphaeria, Lasiobertia, Pulmosphaeria and Yuea (Sordariomycetes incertae sedis), Phytotaxa 258 (2), pp. 153-163 : 156

Immersisphaeria Jaklitsch, Mycotaxon 101: 18 (2007)

Facesoffunginumber: FoF01359

Habitat on hardwood covered by the corticiaceous basidiomycete, Phanerochaete tuberculata (P. Karst.) Parmasto. Sexual morph: Pseudostromata pulvinate, fleshy, yellowish brown. Ascomata immersed, globose to subglobose in cross section, solitary, dark brown to black ostiolar dots present. Ostioles slightly higher than the surface, black, conical. Peridium thin, comprising hyaline, pesudoparenchymatous cells of textura angularis. Hamathecium comprising periphyses emerging from the upper part of peridium, with sparse, hyaline paraphyses, 2.5–4 μm wide at base. Asci 8- spored, unitunicate, cylindrical, short stipitate, thickened at base, without apical apparatus. Ascospores uniseriate, light brown, 2-celled, ellipsoid, smooth-walled, straight to sigmoid germ slit. Asexual morph: undetermined.

Notes:— Immersisphaeria eichleriana (Bres.) Jaklitsch was introduced to replace Hypocrea eichleriana Bres. , a fungicolous fungus. The characters of I. eichleriana are unique and differ from Trichoderma Pers. by having a fungicolous habit with ascomata containing hyaline peridium and cylindrical asci with brown ascospores. Jaklitsch (2007) suggested this fungus can be associated with Hypocreales and Phyllacorales based on the morphology of the hyaline peridium. However due to differences in the other characters, such as reduced stromata, brown ascospores and apically free paraphyses I. eichleriana cannot be placed in either of these orders ( Jaklitsch 2007). He also compared the relationships of Immersisphaeria with Helminthosphaeria Fuckel , which share the fungicolous habitat and also with Coniochaeta (Sacc.) Cooke based on the unicellular brown ascospores in cylindrical asci. Jaklitsch (2007) also suggested the possibility to accommodate this in Xylariaceae . However due to the difference of morphological characters, Immersisphaeria cannot be assigned to any of the mentioned genera or families. Therefore Jaklitsch (2007) placed Immersisphaeria in the Sordariomycetes incertae sedis. In this paper we tentatively placed Immersisphaeria in the Xylariales as genera incertae sedis based on morphological characters such as immersed ascomata and unitunicate, 8-spored asci with small, ellipsoidal, brown ascospores with germ slit, until molecular data and asexual characters are introduced to determine the familial placement.

Type species:— Immersisphaeria eichleriana (Bres.) Jaklitsch, Mycotaxon 101: 18 (2007).

Facesoffunginumber: FoF01360.

Habitat on hardwood covered by the corticiaceous basidiomycete, Phanerochaete tuberculata (P. Karst.) Parmasto. Sexual morph: Pseudostromata 0.1–0.2 mm diam × 0.1 mm thick (x = 0.16 × 0.1 mm, n = 10), pulvinate, surface yellowish brown, black dots present in the host surface. Ascomata 145–185 × 120–180 μm (x = 167 × 162 μm, n = 10), entirely immersed in the host tissue, globose, ellipsoidal to obpyriform, base rounded, solitary or gregarious, visible in the surface of the host as dark brown to black circular dots. Ostioles in cross section 20–40 × 25–40 μm (x = 32 × 36 μm, n = 10) at the apex, papillate, black, visible as tiny black dots, perforation 7–10 μm wide, conical, slightly projecting over the surface of the host. Peridium 19–27 μm wide, well defined, comprising hyaline, pesudoparanchymatous cells of textura angularis. Hamathecium comprising sparse, hyaline paraphyses, 2.5–4 μm (x = 3.1 μm, n = 20) wide, more or less than the asci length. Asci 8-spored, unitunicate, cylindrical, short-stipitate, apex slightly thickened, without apical apparatus, stipe cylindrical or sometimes thickened at the base, spore-bearing parts 45–55 μm long (x = 53 μm, n = 20), stipes 8–18 μm long (x = 12 μm, n = 20). Ascospores 6.5–7 ×3.7–4.3 μm (x = 6.7 × 4.1 μm, n = 20), uniseriate, unicellular, light brown, ellipsoidal, with narrowly rounded ends, with germ slit, straight, up to spore-length, smooth-walled. Asexual morph: Undetermined.