Fungalpedia – Note 587, Uredinopsis
Uredinopsis 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
Uredinopsis was described by Muang (1893) based on U. filicina found on a fern host of Phegopteris vulgaris. Uredinopsis was traditionally located in Pucciniastraceae, Uredinales, Basidiomycetes (Bennell and Henderson 1985; Helfer 2006; Berndt 2008), but it was re-assigned to Milesinaceae (Pucciniales, Pucciniomycetes, Basidiomycota) based on morphology, life cycle and molecular data of three concatenated loci of 28S, 18S, and CO3 (Aime and McTaggart 2021). The phylogenetic relationship demonstrates that Uredinopsis formed a well-supported clade and is closely related to Milesina (McTaggart et al. 2014; Ono et al. 2020). Uredinopsis was described as occurring solely on ferns, characterized by being heteroecious with Abies as alternate hosts, the presence of teliospores formed inside host epidermal cells and smooth or with a few lines of cog-like warts, more or less lanceolate, ellipsoid, clavate or subfusiform urediniospores, usually with a longitudinal band of warts and a generally smooth surface (Fraser 1914; Bell 1924; Faull 1938a, b; Helfer 2006; Berndt 2008). Uredinopsis differs from the similar genus Milesina (both called fir-fern rust) in having more or less lanceolate urediniospores, while Milesina presents echinulate or verrucose urediniospores usually, without pigment produced in cytoplasm (Helfer 2006). Additionally, a monograph was provided by Faull (1938b), and a more recent overview of Uredinopsis species was provided by Hiratsuka (1958b), as well as its closely related genera, Hyalopsora and Milesina.
Uredinopsis is one of the most common genera of fir-fern rust fungi known to parasitize ferns, particularly Aspidiales (Bennell and Henderson 1985), casing disease characterized by the appearance of yellowish spots or blotches on the upper side of infected needles, which later become necrotic and are typically confined by veins (Bell 1924; Faull 1938a, b; Kuprevich and Transchel 1957; Ziller 1959). The alternate stages (aecial stage) of these members occur exclusively on the needles of the conifer genus Abies (Fraser 1912; Bennell and Henderson 1985). Uredinopsis is also an ancient genus with a cosmopolitan distribution (Berndt 2008; McTaggart et al. 2014), with no new species have been discovered in the last 60 years (Index Fungroum August 2024), likely due to the neglect of fern fungi and the insignificance of rust fungi (Bennell and Henderson 1985; Berndt 2008).
Type species: Uredinopsis filicina (Niessl) Magnus
≡ Protomyces filicinus Niessl
Other accepted species: Species Fungorum – search Uredinopsis.
Figure 1 – Two Uredinopsis species on ferns (a–d Type species of Uredinopsis filicina, redrawn from the website of iNaturalist Ecuador (https://ecuador.inaturalist.org/) and Ellis (2001–2024) e–g Uredinopsis pteridis, redrawn from McTaggart et al. 2014). a Abaxial leaf symptoms. b Teliospores. c, d Two types of urediniospores. e Abaxial leaf symptoms. f, g Urediniospores.
References
Bell HP 1924 – Fern rusts of Abies. Botanical Gazette 77:1–31.
Berndt R 2008 – The rust fungi (Uredinales) on ferns in South Africa. Mycological Progress 7:7–19.
Fraser W 1914 – Notes on Uredinopsis mirabilis and other rusts. Mycologia 6:25–28.
Helfer S 2006 – Micro-fungal pteridophyte pathogens. Fern Gazette 17:259–261.
Hiratsuka N 1958 – Revision of taxonomy of the Pucciniastreae: With Special References to Species of the Japanese Archipelago. Kasai Publishing and Printing, Tokyo.
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