Septonema secedens
Septonema secedens Corda, Icon. fung. (Prague) 1: 9 (1837).
Index Fungorum number: IF 153626; Facesoffungi number: FoF 11452, Fig. 1
Description:
Saprobic on host. Sexual morph: Unknown. Asexual morph: Colonies on natural substrate orbicular, densely floccose, dark brown or dark reddish brown, typically confluent and forming irregular patches, occasionally effuse and hairy. Mycelium superficial comprising branched, septate, strongly verruculose, echinulate, pale brown to dark brown ascending hyphae, often anastomosing, interwoven creeping hyphae, often constricted at the septa and forming angular or irregularly swollen cells, 3.1−4.2 μm wide. Conidiophores variable in size, macronematous or semi-macronematous, mononematous, arising terminally or laterally from the hyphae, solitary, erect or somewhat repent, flexuous or sinuous, rarely straight, cylindrical or subcylindrical, mostly branched, septate, occasionally constricted at some septa and breaking along the constrictions, verruculose, smooth, thick-walled, brown to reddish brown, ornamentation vary along the length of the conidiophore. Conidiogenous cells 4.0−9 × 2.3−3.5 µm (x̄ = 5 × 3.0 µm, n = 10), monoblastic or polyblastic, integrated, terminal or intercalary on conidiophores and branches, determinate, cylindrical or subcylindrical, rounded at the apex and somewhat attenuated to the truncate end, with 1−2 inconspicuous conidiogenous loci. Conidia 7−20 × 3.4−4.6 µm (x̄ = 15.1 × 3.9 µm, n = 10), acrogenous or acropleurogenous, cylindrical, subcylindrical or narrowly ellipsoidal, straight or somewhat flexuous, 1 to multiseptate, slightly constricted at some septa, smooth, verruculose, brown to reddish brown, formed in simple or branched, short acropetal chains of 2−4 conidia at conidiophores or branches, each conidium with 0−3 apical or lateral inconspicuous hila or 0−2 per individual conidial cell, apex rounded or slightly truncate, base truncate.
Material examined: The United States, Florida, Collier, Vanderbelt Beach, on Serenoa repens (Arecaceae), 1 January 1978, JLC and JDS (ILL39688).
Fig. 1 Septonema secedens (ILL39688). a–c Herbarium material and appearance of colonies on the host surface. d Squash mount of mycelium. e Conidiophores. f–m Conidiophores, branches and conidia. n–r Conidia. Scale bars: c = 2000 μm, d, e = 50 μm, f, g, n, o = 10 μm, h–m = 20 μm, p–r = 5 μm.
Importance and distribution
There are 55 Septonema epithets in Index Fungorum (2022), but several species have been transferred to other genera such as Bahusakala, Capnodendron, Cladophialophora, Consetiella, Lylea, Ochroconis, Pirozynskiella, Pseudocercospora, Pseudopithomyces, Septocylindrium, Sterigmatobotrys and Taeniolella. Septonema comprises 39 species known on wide range of plants such as Abies alba (Pinaceae), Acer sp. (Sapindaceae), Agave americana (Asparagaceae), Betula pendula (Betulaceae), Cajanus cajan (Fabaceae), Cattleya bowringiana (Orchidaceae), Cunninghamia lanceolata (Cupressaceae), Heterodera glycines (Heteroderidae), Laelia sp. (Orchidaceae), Odontoglossum sp. (Orchidaceae), Picea glauca (Pinaceae), Pinus contorta var. contorta (Pinaceae), Pseudotsuga menziesii (Pinaceae) and Quercus robur (Fagaceae). Septonema is known from Asia (China (Taiwan), Malaysia), Central America (Costa Rica, El Salvador, Panama), Europe (Italy, Poland), North America (Canada, Illinois, North Carolina, Oregon) and South America (Venezuela). Septonema may comprise many more species in unexplored hosts and regions. Septonema needs to be re-collected as molecular data is lacking for the genus.
References
Boehm EWA, Mugambi GKM, Miller AN, Huhndorf SM et al. 2009 – A molecular phylogenetic reappraisal of the Hysteriaceae, Mytilinidiaceae and Gloniaceae (Pleosporomycetidae, Dothideomycetes) with keys to world species. Studies in Mycology 64, 49–83.
Borowska A. 1975 – New species of Bactrodesmium, Corynespora, Septonema and Taeniollela. Acta Mycologica Warszawa 11, 59–65.
Delgado G, Koukol O, Miller A, Piepenbring M. 2019 – Septonema lohmanii G. Delgado & O. Koukol, sp. nov., a New Species in Mytilinidiales (Dothideomycetes) and the Phylogenetic Position of S. fasciculare (Corda) S. Hughes. Cryptogamie Mycologie 40, 3–21.
Holubová-Jechová V. 1978 – Lignicolous Hyphomycetes from Czechoslovakia 5. Septonema, Hormiactella and Lylea. Folia Geobotanica & Phytotaxonomica 13, 421–442.
Hyde KD, Jones EBG, Liu JK, Ariyawansa H et al. 2013 – Families of Dothideomycetes. Fungal Diversity 63, 1–313.
Lunghini D, Toscano F. 1997 – Studies on Mediterranean hyphomycetes. VII. Septonema crispulum anam.-sp. nov. Mycotaxon 63, 329–334.
Schubert K, Braun U. 2007 – Taxonomic revision of the genus Cladosporium s. lat. 6. New species, reallocations to and synonyms of Cercospora, Fusicladium, Passalora, Septonema and Stenella. Nova Hedwigia 84(1–2), 189–208.
Stevenson JA. 1946 – Fungi novi denominati - II. Mycologia 38, 524–533.
Wijayawardene NN, Hyde KD, Lumbsch HT, Liu JK et al. 2018 – Outline of Ascomycota: 2017. Fungal Diversity 88, 167–263.
Recent News
Recent paper to be publishedRecent Genus
NeomedicopsisBoeremia
Gangamyces
Recent Species
Leveillina arduinaeEuryachora sedi
Didymellina iridis
