Fungalpedia – Note 2795, Synaptospora
Synaptospora. Cain.
Citation when using this data: Huang SK et al. 2021 – Fungalpedia.
Index Fungorum, Facesoffungi, MycoBank, GenBank, Fig 1
Classification: Incertae sedis, Sordariales, Sordariomycetidae, Sordariomycetes, Pezizomycotina, Ascomycota, Fungi
Saprobic on wood. Sexual morph: Ascomata perithecial, superficial, gregarious to scattered, globose to subglobose, carbonaceous, with ostiole, black, verrucose, surrounded by setae. Peridium carbonaceous to membranaceous, composed of hyaline to brown cells of textura angularis. Paraphyses septate, cylindrical, evanescent. Asci 2–8-spored, unitunicate, cylindrical to clavate, apex broadly rounded or truncate. Ascospores uni- or bi-seriate, globose to subglobose, aseptate, hyaline when young, becoming pale brown to dark brown, fused in groups. Asexual morph: Undetermined (adapted from Cain 1957b; Huhndorf et al. 1999b; Réblová 2002).
Notes: Cain (1957b) established Synaptospora and introduced two distinctive taxa, S. petrakii (type) and S. tartaricola. The genus has mature ascospores which become fused in groups and Cain (1957b) inferred that this genus is closely related to Bombardia, Podospora and Sordaria, due to its carbonaceous ascomata. Subsequently, S. olandica, S. plumbea and S. setosa were introduced, all of which have fused ascospores, except for S. plumbea with unfused, ellipsoidal ascospores (Huhndorf et al. 1999b; Réblová 2002). Miller et al. (2014) sequenced S. plumbea (ANM963 and SMH3962) and found that it clustered with Helminthosphaeria species. Thus, Synaptospora was transferred to Helminthosphaeriaceae based on phylogenetic analyses (Miller et al. 2014; Hyde et al. 2020; Wijayawardene et al. 2020). We found that S. plumbea is similar to Helminthosphaeria in having globose ascomata, cylindrical asci and brown aseptate, ellipsoidal, unfused ascospores, differing from other Synaptospora species with fused ascospores. Phylogenetically, S. plumbea nested in Helminthosphaeriaceae (61%ML). Therefore, we recommend transferring S. plumbea to Helminthosphaeria. The remaining four Synaptospora species have globose ascomata, cylindrical asci and globose, fused ascospores, but no molecular information is available. We place Synaptospora in Sordariales genera incertae sedis pending future work.
Type species: Synaptospora petrakii Cain, Beih. Sydowia 1: 5 (1957) [1956].
Other accepted species: Species Fungorum – search Synaptospora.
Figure 1 – Synaptospora petrakii: a–c, e, f, h–o, q–x (TRTC-51203); d, g, p (TRTC-51205). a Herbarium material. b Ascomata on host. c, d Ascoma in cross section. e Peridium. f, g Setae. h Hyphae of subiculum. i Septate paraphyses. j Asci with paraphyses. k Asci. l Apex of ascus (stained in Melzer’s reagent). m–q, s–v Immature to mature ascospores (m–q 3-septate; s–t 2-septate; u–v 4-septate). r, w Ascospores breaking into individual cells. x Individual spore cells. Scale bars: b = 500 µm, c. d. j = 100 µm, e. k = 50 µm, f–i = 20 µm, l–x = 10 µm.
References
Cain RF 1957b – Synaptospora, a new genus of amerosporous Ascohymeniales (Ascomycetes). Beihefte Zur Sydowia 1:4–8.
Huhndorf SM, Fernández F, Candoussau F 1999b – Two new species of Synaptospora. Sydowia 51:176–182.
Huhndorf SM, Fernández F, Candoussau F 1999b – Two new species of Synaptospora. Sydowia 51:176–182.
Réblová M 2002 – Synaptospora olandica, a new species from Sweden. Sydowia 54(2):248–255.
Entry by
Shi-Ke Huang, State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Guiyang 550025, China, The Engineering Research Center of Southwest Bio-Pharmaceutical Resources, Ministry of Education, Guizhou University, Guiyang 550025, Guizhou Province, China, Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai 57100, Thailand, School of Science, Mae Fah Luang University, Chiang Rai 57100, Thailand, The Mushroom Research Centre, Guizhou University, Guiyang 550025, China
Published online 18 June 2026