Fungalpedia – Note 596, Uredo
Uredo Pers.
Citation when using this data: Zhang et al. 2025 (in prep.) – Fungalpedia, Basidiomycota.
Index Fungorum, Facesoffungi, MycoBank, GenBank, Fig. 1
Classification: Pucciniaceae, Pucciniales, Incertae sedis, Pucciniomycetes, Pucciniomycotina, Basidiomycota, Fungi
Uredo was described by Persoon (1794) to accommodate three species, namely U. betae, U. euphorbiae–helioscopiae and U. fabae. Later, Uredo was validly established by Persoon (1801) without designing the type species, and accepted 30 species. Uredo betae, U. euphorbiae–helioscopiae and U. fabae have all been the lectotype of Uredo (Laundon 1965, 1967; Hennen et al. 2005). The history of the typification was reviewed by Laundon (1970), who proposed U. betae as the type species of Uredo.
The generic name Uredo was established and used for uredinial anamorphs of rust fungi belonging to many families, such as Melampsoraceae and Pucciniaceae (Simpson et al. 2006; Aime et al. 2018). Many members of the asexual genus Uredo have subsequently been shown to link with various asexual genera and have been reduced to synonymy, such as Anthracoidea, Mycosarcoma, Ustilago and Tilletia (Aime et al. 2018; Aime and McTaggart 2021). The phylogenetic affinity of this genus is uncertain, and, for a time, it was considered as Pucciniales incertae sedis in Pucciniomycetes (Aime et al. 2018; He et al. 2019). Aime et al. (2018) recommended using the generic name Uromyces instead of Uredo due to its problematic phylogenetic affinity and the common usage of the generic name “Uromyces”. However, this conclusion was not universally accepted (He et al. 2019; Berndt 2020). In more recent studies, Uredo myricae sp. nov. was found on Myrica sp. (Myricaceae) in the South African Cape region (Berndt 2020), and Uredo longa was described as new to science by Zhuang et al. (2021a, 2017b). Furthermore, Cummins and Hiratsuka (2003) emphasized the general usage of the anamorph genus Uredo, strictly defining it as a morphological concept, rather than by its position as aecium or uredinium in its life cycle. We keep this processing status with using the name Uredo following recent studies due to the lack of systematic research on a large number of Uredo species, which are located in several different families. Direct synonymization with Uromyces would cause even greater confusion.
Uredo is a group of rust fungi characterized by asexual morph that is biotrophic on various plants, with obovoid, ellipsoid, triangular-obovate, or amorphous urediniospores with obscure or distinct germ pores, and hyaline to golden to yellow brown spore wall (Cummins and Hiratsuka 2003; Simpson et al. 2006; Salazar-Yepes and Buriticá Céspedes 2008; Berndt 2009; de Carvalho Jr and Hennen 2010; Berndt and Wood 2012; Aime et al. 2018). There are 19 Uredo species including two unidentified species associated with pteridophytes, belonging to 11 families of pteridophytes, and a worldwide distribution (Table 2). Further study is needed to determine the natural classification of these Uredo species (Aime et al. 2018; Aime and McTaggart 2021).
Type species: Uredo betae Pers.
= Mapea Pat. Bull. Soc. mycol. Fr. 22: 46 (1906).
= Nigredo (Pers.) Roussel, Fl. Calvados, Edn 2: 47 (1806).
= Peridipes Buritica´ & J.F. Hennen, Revta Acad. colomb. cienc. exact. fis. nat. 19(no. 72): 50 (1994).
= Rubigo (Pers.) Roussel, Fl. Calvados, Edn 2: 46 (1806).
= Trichobasis Le´v., Dict. Univ. Hist. Nat. 12: 785 (1849).
Other accepted species: Species Fungorum – search Uredo.
Figure 1 – The development of teliospores of Uredo betae. Redrawn from the website (https://luirig.altervista.org/pics/display.php?pos=77211).
References
Cummins GB, Hiratsuka Y 2003 – Illustrated genera of rust fungi, 3rd Edn. St. Paul, MN: American Phytopathological Society.
Laundon GF 1965 – The generic names of Uredinales. Mycological Papers 99:1–24.
Laundon GF 1970 – lectotype for Uredo. Taxon 19: 947–947.
Persoon, CH. 1794 – Dispositio methodica fungorum. Neues Magazin für die Botanik in ihrem ganzen Umfange 1:81–128.
Persoon CH 1801 – Synopsis methodica fungorum, vol 2. Henricus Dieterich, Göttingen.
Zhuang WY, Zheng HD, Ren F 2017b – Taxonomy of the genus Bisporella (Helotiales) in China with seven new species and four new records. Mycosystem 36:401–420.
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