Fungalpedia – Note 2873, Polycoccum
Polycoccum Saut. ex Körb.
= Lophothelium Stirt., Scott. Naturalist 9: 37 (1887).
Type: Lophothelium acervatum Stirt.
Citation when using this data: Meng QF et al. – Fungalpedia.
Index Fungorum, faceoffungi, MycoBank, GenBank, Fig 1.
Classification: Polycoccaceae, Pleosporales, Dothideomycetes orders incertae sedis, Pezizomycotina, Ascomycota, Fungi.
Polycoccum was originally established by Körb. (1865b) to accommodate the lichenicolous species Polycoccum sauteri Körb., which was initially found on Stereocaulon condensatum Hoffm. Later, Santesson (1960) reintroduced this genus and designated Polycoccum trypethelioides (Th. Fr.) R. Sant. as the type species of this genus. Vězda (1969) further developed a key to the lichenicolous species within Polycoccum. A phylogenetic analysis conducted by Ertz et al. (2015b) revealed that Polycoccum and Clypeococcum form a single clade in Trypetheliales clade. Consequently, Polycoccaceae was established, and Lophothelium was synonymized with Polycoccum, leading to the transfer of its sole species, Lophothelium acervatum. The genus is characterized by the formation of gall-like ascomata on the host thallus, gelatinous hamathecia, broadly cylindrical to subclavate asci, and broadly ellipsoid, dark brown to almost black, thick-walled, ornamented ascospores (Hawksworth et al. 1988b, Ertz et al. 2015b).
Among the 85 records listed in Index Fungorum (2025), 62 were retained within this genus Polycoccum, while others have been transferred to different genera or synonymized. Polycoccum arnoldii (Hepp) D. Hawksw. was transferred to Sphaerellothecium arnoldii by Hafellner (2019a), but it is still listed under Polycoccum in MycoBank, leading to its exclusion from our checklist. Polycoccum condensatum Saut. is listed in both Index Fungorum (2025) and MycoBank (2025) but was considered invalid by Hawksworth et al. (1988), so it was also excluded from our checklist. Polycoccum opulentum was transferred from Endococcus opulentus Th. Fr. & Almq. by Arnold (1891). Although this species was subsequently transferred to Didymosphaeria opulenta (1905) and Discothecium opulentum (1913), these combinations were invalid or illegitimate. Polycoccum psoromatis was transferred by Hafellner (2018) from Sphaeria psoromatis A. Massal., but MycoBank erroneously lists Clypeococcum psoromatis as the current name in. Polycoccum sauteri was included by Hawksworth (1988) as a synonym of P. trypethelioides, a record found in MycoBank but not in the synonym list of P. trypethelioides in Index Fungorum (2025) and Species Fungorum (2025). Polycoccum stellulatae was transferred from Didymosphaeria bryonthae var. stellulatae Vouaux by Hafellner (2015), but the basionym was incorrectly classified as the current name in MycoBank (2025).
Type species: Polycoccum trypethelioides (Th. Fr.) R. Santo.
= Polycoccum sauteri Körb., holotype.
Other accepted species: Species Fungorum – search Polycoccum.
Figure 1 – Polycoccum trypethelioides redrawn from Ertz et al. (2015b). a Galls on Stereocaulon with immersed ascomata. b Section through ascoma. c Ascus with ascospores. d Ascospores in water. Scale bars: a = 200 μm, b = 50 μm, c= 20 μm, d = 5 μm.
References
Hafellner J. 2018 – Lichenicolous Biota (Nos 271–300). Fritschiana 90, 1–22.
Hafellner J. 2019a – Lichenicolous Biota (Nos 301–320). Fritschiana 94, 25–42.
Körber GW. 1865b – Parerga lichenologica. Ergänzungen zum Systema lichenum Germaniae 5, 385–501.
Santesson R. 1960 – Lichenicolous fungi from northern Spain. Svensk Bot. Tidskr. 54, 499–522.
Entry by
Meng QF, Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai, 57100, Thailand and School of Public Health, Zunyi Medical University, Guizhou 563000, China.
Published online 23 July 2026