Fungalpedia – Note 562, Hyalopsora.
Hyalopsora Magnus.
Citation when using this data: Zhang et al. 2025 (in prep.) – Fungalpedia, Basidiomycota.
Classification: Pucciniastraceae, Pucciniales, Incertae sedis, Pucciniomycetes, Pucciniomycotina, Basidiomycota, Fungi
Index Fungorum, Facesoffungi , MycoBank, GenBank, Fig. 1
Hyalopsora was introduced by Magnus (1901) and is one of three rust fungi restricted to ferns with alternate hosts (Berndt 2008). Hyalopsora is similar to the other two genera of fern rust fungi (Milesina and Uredinopsis) in their life mode, but it can be distinguished from them (Berndt et al. 1994; Berndt 2008; Smith 2015). Morphologically, Hyalopsora differs from the other two genera due to its echinulate or verrucose urediniospores with hyaline walls and orange pigmented cytoplasm, presentation of amphispores, and a vesicular haustorium (Hiratsuka 1936; Cummins and Hiratsuka 2003; Helfer 2006). Phylogenetically, Hyalopsora constitutes a monophyletic clade within Pucciniastraceae, forming a separate lineage from Milesina and Uredinopsis, which are located in Milesinaceae (Aime and McTaggart 2021; Wang et al. 2021). Furthermore, it is noteworthy that the only genus in the family Pucciniastraceae that infects fern plants is Hyalopsora (Aime and McTaggart 2021).
All known Hyalopsora species have been found associated with pteridophytes in their dikaryotic phase (Hiratsuka 1936; Berndt et al. 1994), and these members are mainly distributed in temperate to cold areas, especially where their alternate hosts (Abies species) are found (Hiratsuka 1958; Cummins and Hiratsuka 2003; Ji et al. 2018). The most recent taxonomic study of Hyalopsora was conducted by Wang et al. (2021), introducing two species and a new geographical record for China, as well as providing an updated phylogenetic relationship of Hyalopsora species and related taxa based on ITS and LSU sequence data. Furthermore, a checklist of Hyalopsora on ferns and their allies was provided in this study, along with their hosts and distribution.
Type species: Hyalopsora aspidiotus (Peck) Magnus.
Other accepted species: Species Fungorum – search Hyalopsora.
Figure 1 – Hyalopsora species on ferns (a–c Type species of Hyalopsora aspidiotus; d–g A case of Hyalopsora hakodatensis found on fern). a Uredinia on lower leaf surface of Gymnocarpium jessoense. b Amphispores on G. jessoense. c Urediniospores on G. disjunctum. d Uredinia on lower leaf surface of Deparia orientalis. e Vertical section of a sorus of amphispores on Lunathyrium sp. f Urediniospores on D. orientalis. g Amphispores on Lunathyrium sp. Redrawn from Ji et al. (2018).
References
Berndt R 2008 – The rust fungi (Uredinales) on ferns in South Africa. Mycological Progress 7:7–19.
Cummins GB, Hiratsuka Y 2003 – Illustrated genera of rust fungi, 3rd Edn. St. Paul, MN: American Phytopathological Society.
Helfer S 2006 – Micro-fungal pteridophyte pathogens. Fern Gazette 17:259–261.
Hiratsuka N 1936 – A monograph of the Pucciniastreae. Tottori Agricultural College, Tottori, Japan.
Smith PA 2015 – Rust fungi on ferns. Field Mycology 16:49–53.
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