Fungalpedia – Note 558, Desmella
Desmella Syd. & P. Syd.
Citation when using this data: Zhang et al. 2025 (in prep.) – Fungalpedia, Basidiomycota.
Index Fungorum, Facesoffungi, MycoBank, GenBank, Fig. 1
Classification: Incertae sedis, Pucciniales, Incertae sedis, Pucciniomycetes, Pucciniomycotina, Basidiomycota, Fungi
Desmella, a genus of fern rust, was introduced by Sydow (1919) to accommodate four new combinations, namely Desmella aneimiae, D. gymnogrammes, D. mbatobiensis and D. superficialis. Recently, based on 28S nuclear rDNA sequence data, a phylogenetic relationship was reconstructed revealing Desmella in Pucciniaceae (Pucciniales, Pucciniomycetes, Basidiomycota) (Aime and McTaggart 2021), which is closely related to Sphaerophragmiaceae sensu stricto (Okane et al. 2021). Morphologically, the genus is characterized by scab symptoms caused by minute, subepidermal sori, short pedicellate,globose, elliptical or oval urediniospores arising from the apices of the hypha, and bicellular, hyaline teliospores (Sydow 1919; Arthur 1929; Cummins 1940; Thirumalachar and Cummins 1948; Ono 2020). Currently, five species are accepted in Desmella (Sydow 1919; Okane et al. 2021). The genus is known exclusively from its uredinial and telial stages of the life cycle, with no known alternate host (Hennen and Ono 1978; Cummins and Hiratsuka 2003; Ono 2020). It exhibits a clear preference for obligatory fern host parasitism, especially on tropical ferns (Faull 1947; Hennen and Ono 1978; Cummins and Hiratsuka 2003; Ono 2020; Okane et al. 2021). Although there are only five species, Desmella is one of the most commonly occurring on ferns (Helfer 2006). Among these, D. aneimiae infects 19 genera of ferns and their allies. Desmella superficialis is a common and widely distributed species, found on more than 20 kinds of ferns. Notably, D. lygodii is found only on Lygodium spp. (Schizaeaceae, Schizeaeales), and is likely restricted to this fern genus.
Type species: Desmella aneimiae Syd. & P. Syd. Uredo aneimiae Henn.
≡ Uredo aneimiae Henn.
Other accepted species: Species Fungorum – search Desmella.
Figure 1 – Desmella aneimiae. a Mature uredinia densely distributed on the leaf surface of Christella dentata and Nephrolepis exaltata subsp. hawaiiensis. c Urediniospores focus on tangential plane to show spines on the wall surface. d Urediniospores focused on median plane. Redrawn from Ono (2020). b Superstomatal telial development of Desmella species, showing structure in longitudinal section. Redrawn from Hennen and Ono (1978)
References
Arthur JC 1929 – Another fern rust of the genus Desmella. Mycologia 21:77–78.
Cummins GB 1940 – Notes on some Uredinales. Annales Mycologici 38:335–338.
Cummins GB, Hiratsuka Y 2003 – Illustrated genera of rust fungi, 3rd edn. American Phytopathological Society, St. Paul, MN.
Faull JH 1947 – Tropical fern hosts of rust fungi. J Arnold Arboretum 28:309–319.
Helfer S 2006 – Micro-fungal pteridophyte pathogens. Fern. Gazette 17:259–261.
Hennen JF, Ono Y 1978 – Cerradoa palmaea: the first rust fungus on Palmae. Mycologia 70:569–576.
Sydow H 1919 – Mykologische Mitteilungen Ann Mycol 17:33–47.
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