Fungalpedia – Note 3040, Placuntium
Placuntium Ehrenb.
Citation when using this data: Wang QT et al. 2023 – Fungalpedia.
Index Fungorum, Faceoffungi, MycoBank, GenBank.
Classification: Rhytismataceae, Rhytismatales, Leotiomycetidae, Leotiomycetes, Pezizomycotina, Ascomycota, Fungi.
The genus Placuntium was introduced by Ehrenberg (1818: 17) to contain four species, including Xyloma andromedae Pers. A short but nomenclaturally acceptable description on page 29 of this work validates the genus, and Höhnel (1917a, b) lectotypified Placuntium with P. andromedae (Pers.) Ehrenb. The generic name is thus available for the species of the Lyonia & Andromeda (Vaccinioideae) clade.
Parasitic on species of Vaccinioidae (Ericaceae). Stromata appearing on living leaves, often covering most or even the entire adaxial surface of the leaf. Ascomata developing on dead attached or fallen leaves, circular or elliptical to irregular, opening by one longitudinal or various irregular splits. Lips absent. Paraphyses filiform, sometimes branched, markedly curled or coiled (but not swollen) at the apex. Ascospores clavate, with conspicuous gelatinous sheaths.
Notes: The Lyonia & Andromeda (Vaccinioideae) clade received high support values in the phylogenetic trees (Fig. 1; Wang QT et al. 2023 & Supplementary Figs. 1-3), but the micromorphological characteristics of specimens Hou 1105, Hou 1106 and Hou 1107 could not be observed due to immaturity of the ascomata. Species of the Lyonia & Andromeda (Vaccinioideae) clade apparently differ from other Rhytisma-like species parasitic on species of Ericaceae by ascospores with conspicuous gelatinous sheaths, although more data are needed before this characteristic can be regarded as diagnostic. The Lyonia & Andromeda (Vaccinioideae) clade contains two subclades, one containing collections from Lyonia (HOU 1105, HOU 1106 and HOU 1107) and the other Placuntium andromedae, parasitic on Andromeda polifolia L. As the specimens from Lyonia subclade are all immature, further collections are needed. They may be assigned to the conidial genus Aoria Cif., the type of which causes tar spot of Lyonia in the Dominican Republic and was considered by Sutton (1980) as a likely candidate for an anamorph of Rhytisma.
Type species: Placuntium andromedae (Pers.) Ehrenb. 1818.
Other accepted species: Species Fungorum – search Placuntium.
References
Ehrenberg CG. 1818 – Sylvae Mycologicae Berolinenses. Ehrenberg, Berlin. 1–36.
Höhnel F. von. 1917a – Mycologische Fragmente [nos 120–190]. Annales Mycologici 15: 293–383.
Höhnel F. von. 1917b – System der Phacidiales. Berichte der Deutschen Botanischen Gesellschaft 35: 416–422.
Sutton BC. 1980 – The Coelomycetes. Fungi Imperfecti with Pycnidia, Acervuli and Stromata. Kew: Commonwealth Mycological Institute.
Entry by
Qiu-Tong Wang and Mei-Jun Guo, College of Life Science, Capital Normal University, Xisanhuanbeilu 105, Haidian, Beijing 100048, China.
Published online 27 August 2026