Polycladium

Fungalpedia – Note 577, Polycladium

 

Polycladium Ingold

Citation when using this data: Zhang et al. 2025 (in prep.) – Fungalpedia, Ascomycota.

Index Fungorum, Facesoffungi, MycoBank, GenBank, Fig. 1

Classification: Incertae sedis, Incertae sedis, Incertae sedis, Incertae sedis, Pezizomycotina, Ascomycota, Fungi.

The hyphomycetous genus Polycladium was introduced by Ingold (1959) to accommodate the type species P. equiseti based on its unique morphology and comparison with two most similar genus, Tricladium and Varicosporium. Polycladium is characterized by unbranched, simple conidiophore arising from a persistent apical cell, as well as sessile and lateral conidia consisting of a long filamentous main axis bearing 2–4 lateral branches, one or two lower members of which may secondarily branch (Ingold 1959). Polycladium equiseti was considered to be placed in Tricladium and Varicosporium based on its conidial characteristics, but was excluded from Tricladium due to the lack of secondary laterals of conidia, and from Varicosporium due to the position of conidia to the conidiophores (Ingold 1942, 1943, 1959). Currently, Polycladium, including the species P. equiseti, was found on natural substrates of submerged, disarticulated, bleached internodes of Equisetum fluviatile in an aquatic habitat (Ingold 1959). Polycladium is currently treated as Ascomycota genera incertae sedis (Wijayawardene et al. 2022; Hyde et al. 2024c). Fresh collections are needed to place Polycladium in a natural grouping, and clarify its host relationship.

Type species: Polycladium equiseti Ingold, Trans.

Other accepted species: Species Fungorum – search Polycladium.

 

Figure 1 – Polycladium equiseti. a–d, f Conidiophores bearing conidia. e Small part of “f” at higher magnification. g–i Liberated conidia. Redrawn from Ingold (1959).

 

References

Hyde KD, et al. 2024c – The 2024 outline of fungi and fungus-like taxa. Mycosphere (in press).

Ingold C 1942 – Aquatic hyphomycetes of decaying alder leaves. Transactions of the British Mycological Society 25 (4):339–IN336.

Ingold C 1943 – Further observations on aquatic hyphomycetes of decaying leaves. Transactions of the British Mycological Society 26:104-IN102.

Ingold C 1959 – Polycladium equiseti gen. nov., sp. nov.: an aquatic hyphomycete on Equisetum fluviatile. Transactions of the British Mycological Society 42:112–114.

Wijayawardene NN, Hyde KD, Dai DQ, Sánchez-García M, Goto BT, Saxena R, Erdoğdu M, Selçuk F, Rajeshkumar KC, Aptroot A, Błaszkowski J, Boonyuen N, da Silva GA, de Souza FA, Dong W, Ertz D, Haelewaters D, Jones EBG, Karunarathna SC, Kirk PM, Kukwa M, Kumla J, Leontyev DV, Lumbsch HT, Maharach chikumbura SSN, Marguno F, Martínez-Rodríguez P, Mešić A, Monteiro JS, Oehl F, Pawłowska J, Pem D, Pfliegler WP, Phil lips AJL, Pošta A, He MQ, Li JX, Raza M, Sruthi OP, Suetrong S, Suwannarach N, Tedersoo L, Thiyagaraja V, Tibpromma S, Tkalčec Z, Tokarev YS, Wanasinghe DN, Wijesundara DSA, Wimalaseana SDMK, Madrid H, Zhang GQ, Gao Y, Sánchez Castro I, Tang LZ, Stadler M, Yurkov A, Thines M 2022 – Out line of Fungi and fungus-like taxa—2021. Mycosphere 13:53–453.

 

Entry by 

Jing-Yi Zhang, School of Food and Pharmaceutical Engineering, Guizhou Institute of Technology, Guiyang, 550025, People’s Republic of 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, Guizhou Key Laboratory of Agricultural Microbiology, Guizhou Academy of Agricultural Sciences, Guiyang, 550009, People’s Republic of China.

 

Published online 11 June 2025

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