Revisions of British and Irish Lichens Volume 3 Ostropales: Coenogoniaceae January 2021 Cover image: Coenogonium luteum, overgrowing mosses on bark of Magnolia sp., Logan Botanic Garden, Wigtownshire. Revisions of British and Irish Lichens is a free-to-access serial publication under the auspices of the British Lichen Society, that charts changes in our understanding of the lichens and lichenicolous fungi of Great Britain and Ireland. Each volume will be devoted to a particular family (or group of families), and will include descriptions, keys, habitat and distribution data for all the species included. The maps are based on information from the BLS Lichen Database, that also includes data from the historical Mapping Scheme and the Lichen Ireland database. The choice of subject for each volume will depend on the extent of changes in classification for the families concerned, and the number of newly recognized species since previous treatments. To date, accounts of lichens from our region have been published in book form. However, the time taken to compile new printed editions of the entire lichen biota of Britain and Ireland is extensive, and many parts are out-of-date even as they are published. Issuing updates as a serial electronic publication means that important changes in understanding of our lichens can be made available with a shorter delay. The accounts may also be compiled at intervals into complete printed accounts, as new editions of the Lichens of Great Britain and Ireland. Editorial Board Dr P.F. Cannon (Department of Taxonomy & Biodiversity, Royal Botanic Gardens, Kew, Surrey TW9 3AB, UK). Dr A. Aptroot (Laboratório de Botânica/Liquenologia, Instituto de Biociências, Universidade Federal de Mato Grosso do Sul, Avenida Costa e Silva s/n, Bairro Universitário, CEP 79070-900, Campo Grande, MS, Brazil) Dr B.J. Coppins (Royal Botanic Garden, Inverleith Row, Edinburgh EH3 5LR, UK) Mr A. Orange (Department of Natural Sciences, National Museum of Wales, Cardiff CF10 3NP, UK) Mr N.A. Sanderson (3 Green Close, Woodlands, Southampton, Hampshire SO40 7HU, UK) Dr J.A. Simkin (School of Natural and Environmental Science, Newcastle University, Newcastle upon Tyne NE1 7RU, UK) Dr R. Yahr (Royal Botanic Garden, Inverleith Row, Edinburgh EH3 5LR, UK) Downloads can be obtained from the British Lichen Society website at https://www.britishlichensociety.org.uk/content/lgbi3 Made available under Creative Commons Licence ISSN 2634-7768 CC BY-SA © British Lichen Society, 6 January 2021 Revisions of British and Irish Lichens vol. 3 Ostropales: Coenogoniaceae including the genus Coenogonium by Paul Cannon Royal Botanic Gardens, Kew, Surrey TW9 3AB, UK; email p.cannon@kew.org Jiří Malíček Institute of Botany, Czech Academy of Sciences, Zámek 1, CZ-252 43 Průhonice, Czech Republic Neil Sanderson 3 Green Close, Woodlands, Southampton, Hampshire, SO40 7HU, UK Barbara Benfield Penspool Cottage, Plymtree, Cullompton, Devon EX15 2JY Brian Coppins Royal Botanic Garden, Inverleith Row, Edinburgh EH3 5LR, UK Janet Simkin School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK This publication can be cited as: Cannon, P., Malíček, J., Sanderson, N., Benfield, B., Coppins, B. & Simkin, J. (2021). Ostropales: Coenogoniaceae, including the genus Coenogonium. Revisions of British and Irish Lichens 3: 1-4. 2 COENOGONIACEAE Stizenb. (1862) The Coenogoniaceae as currently circumscribed (Lücking et al. 2016) contains only the genus Coenogonium, so the description below constitutes that of the family. COENOGONIUM Ehrenb. (1820) Thallus crustose (in British species; elsewhere the genus includes fruticose and pulvinate growthforms), thin and inconspicuous or well-developed, smooth or granular, usually grey-green, isidiate in one British species. Photobiont Trentepohlia. Ascomata apothecia, sessile, marginate, concaveurceolate to flat, pinkish-white, pale yellow (at least when young), to orange, the margin concolorous or rarely slightly paler than the disc. Thalline margin absent. True exciple colourless to pale brown in section, composed of globose to angular tissue with an outer layer of weakly vertically oriented hyphae. Hymenium I+ blue. Epithecium indistinct. Hypothecium colourless. Hamathecium of distinctly septate paraphyses, sometimes branched near the apex, with ± swollen to moniliform apical cells. Asci 8-spored, narrowly cylindrical, the wall thin, not fissitunicate, sometimes with a minute amyloid ring below the apex. Ascospores ellipsoidal, 1-septate (in British species), colourless, smooth, without a perispore. Conidiomata pycnidia, one-half to three-quarters immersed, yellowish or whitish-pink, the wall colourless. Conidiogenous cells arising singly or several together from branched supporting cells, cylindrical or bottle-shaped. Conidia ellipsoidal, aseptate, colourless, sometimes biguttulate. Chemistry: no lichen products detected by TLC. Ecology: in humid, shaded or sheltered habitats, on leaves, over mosses, or on mainly acidic bark. This is a quite large genus (with around 90 species) from moist temperate and tropical habitats, including many leaf-inhabiting species. Species were included in the genus Dimerella Trevisan (1860) in the second edition of this volume (see Benfield et al. 2009). That differs only in the crustose rather than filamentous thallus, and as this was considered to be phylogenetically insignificant, Rivas Plata et al. (2006) merged the two genera. Molecular data are sparse, however, and further changes may be needed. Absconditella species have chlorococcoid rather than Trentepohlia algae, have an I– (or reddish) hymenium, and indistinctly septate paraphyses. Gyalecta species are also similar macroscopically to Coenogonium, but have multiseptate ascospores. Literature Alvarez Andrés & Carballal Durán (2001), Benfield et al. (2009), Kauff & Büdel (2005), Lücking et al. (2016), Rivas Plata et al. (2006), Resl et al. (2015). 1 Apothecia yellow-orange, 0.4–2 mm diam. ............................................................................................. 2 Apothecia variously coloured, not yellow-orange, 0.2–0.5 mm diam. ..................................................... 3 2(1) Thallus lacking isidia; frequently fertile; conidia often present, 3–4 (–5) × 1.5–2 µm ...................luteum Thallus with coralloid isidia, forming dense mounds away from apothecia; rarely fertile ......... confusum 3(1) Apothecia white to pale cream or pinkish, not strongly constricted at the base; hymenium 70–90 µm tall; conidia 6–8 × 2–2.5 µm ............................................................................................ pineti Apothecia pinkish beige to orange-brown, ± constricted at the base; hymenium 90–120 µm tall; conidia not known ................................................................................................................ tavaresianum 3 Coenogonium confusum Malíček & Sanderson ined. NT IR Porina rosei auct. br. pro maxima parte Thallus superficial, grey green to whitish, supporting abundant coralloid isidia, usually green, grading to pale ochre-orange where well lit, with a glossy surface, forming dense mounds away from the apothecia, more discrete near apothecia, 20– 50 µm diam., with frequent constrictions and branching, with a compact clear cortex several cells thick surrounding up to four algal filaments. Apothecia 0.5–1.5 mm diam., sessile on the thallus (not when on isidia), distinctly constricted at the base, disc yellow-orange with pale creamy-yellow, often flexuose margins; hymenium 80– 110 µm tall; paraphyses ca 1.5 µm diam., the apical cells to 4 µm diam. Ascus without an amyloid ring around the pore. Ascospores 9–11 × 2.5–3.0 µm. Pycnidia present but no data available. BLS 2787. On a wide range of tree species with base-rich bark as well as on mossy rocks, in ancient woodland; widespread but local. S.W. England, Wales, S.W. Highlands, Ireland. Very rarely fertile and long overlooked as the similar looking but much rarer Porina rosei. True P. rosei is also often sterile, but is darker orange with matt, softer-looking isidial mounds with narrower isidia, up to 27 µm diam., and a thinner clear cortex of a single layer of irregular rounded cells surrounding a single algal filament. C. confusum is very similar to the New Zealand species C. fruticulosum (Ludwig 2014), except based on limited fertile material available, the hymenium is taller and the isidia appear more densely packed in the European species. It does not resemble any of the other varied tropical and austral isidiate Coenogonium species; see Aptroot & Cáceres (2018). Enterographa brezhonega is occasionally parasitic on C. confusum and rarely on C. luteum, and could be easily mistaken as myxomycete fruit-bodies or blobs of Lepraria; however, if looked at closely the convoluted white lirellae are highly distinctive. Coenogonium luteum (Dicks.) Kalb & Lücking (2000) LC Dimerella lutea (Dicks.) Trevis. (1880) Thallus evanescent or thin, effuse, ± unevenly scurfy, pale grey-green, occasionally orange-grey in patches when fresh. Apothecia 0.4–2 mm diam., distinctly constricted at the base; disc concave at first but soon flat or slightly convex, bright yelloworange, with paler, often flexuose margins, but apothecia may be almost colourless and translucent in very wet or shaded conditions; hymenium 50–80 µm tall; paraphyses 1.5–2.5 µm diam., the apical cells to 4.5 µm. Ascus without an amyloid ring around the pore. Ascospores (6–) 8–11 × (2–) 2.5–3.5 µm. Pycnidia half to three-quarters immersed in the thallus, 150–250 µm diam., pale yellowish, the wall colourless. Conidia 3–4 (–5) × 1.5–2 (–2.5) μm, ellipsoidal, aseptate, colourless, sometimes biguttulate. BLS 0490. On bark and associated bryophytes and occasionally on siliceous rocks in humid, shaded situations, and on mosses on soil; locally frequent. S. & W. Britain, throughout Ireland. In England it has recently spread east, probably in response to the decline in acidifying air pollution and potentially also warmer temperatures. Rarely parasitised by Enterographa brezhonega. When sterile the continuous grey-green thallus is diagnostic, and a few pycnidia are usually present. Coenogonium pineti (Ach.) Lücking & Lumbsch (2004) Dimerella pineti (Ach.) Vězda (1975) Thallus evanescent or ± thinly continuous, smooth to ± scurfy, grey-green to oily greenish black. Apothecia 200–500 µm diam., sessile, not strongly constricted at the base, disc concave to ± flat, white to pinkish-white or pale cream, the margin concolorous; hymenium 70–90 µm tall; epithecium indistinct; paraphyses 1–2 µm diam., the apical cells to 3.5 µm. Ascus apex slightly thickened to give an amyloid ring around the pore. Ascospores (8.5–) 9–14 (–15) × (2–) 2.5–4 (–4.5) µm. Pycnidia frequent, 100–220 µm diam., whitish, the wall colourless; conidia 6–8 × 1.8–2.5 µm, cylindric, biguttulate, with a ± clear, median constriction. BLS 0489. On shaded, ± acid bark, occasionally also on base rich very shaded bark, more rarely on wood, mosses, rocks, old leather, or soil; common and widespread but LC 4 easily overlooked. It can be very inconspicuous during dry periods. Throughout Britain, more frequent to the N.E. in Ireland. In the field, specimens with only or predominantly pycnidia only can resemble a Porina. When on wood, rocks or soil, C. pineti needs to be carefully compared with Absconditella species. Coenogonium tavaresianum (Vězda) Lücking, Aptroot & Sipman (2006) Nb Dimerella tavaresiana Vězda (1969) Thallus effuse, immersed to thinly superficial, then consisting of minute granules, 25–30 µm diam. or larger verrucose units, to ca 100 µm diam., dull olive-green to paler glaucous green. Apothecia 200–250 (–350) µm diam., sessile, ± constricted at the base, disc concave to ± flat, pale to medium orange-brown, the margin sometimes slightly darker; hymenium 90–120 µm tall; epithecium indistinct; hypothecium poorly developed, colourless; paraphyses 1–2 µm diam., the apical cells to 3.5 µm. Asci without an amyloid ring around the pore. Ascospores (8.5–) 10–12 (–15) × 3–4 µm. Pycnidia not known. BLS 2695. On bark of veteran Quercus trees, particularly in crevices and rain tracks. Distribution incompletely known, but recorded from E. Wales (Montgomery) and central S, to S. W. England (Devon, Herefordshire, Hampshire, Oxfordshire, Buckinghamshire) Has the appearance of a Gyalecta or Pachyphiale species, especially P. carneola, but the small toffee coloured apothecia are a distinctive colour and it has one- rather than multi-septate ascospores. Literature Alvarez Andrés, J. & Carballal Durán, R. (2001). The genus Dimerella (Gyalectales, Ascomycotina) in Peninsular Spain and Portugal. Nova Hedwigia 73: 409-418. Aptroot, A, & Cáceres, M. E. S. (2018) Coenogonium upretianum (Ascomycota: Coenogoniaceae), a new corticolous lichen species from Brazil. Cryptogam Biodiversity and Assessment. 2456-0251: 11-13 Benfield, B., Purvis, O.W. & Coppins, B.J. (2009). Dimerella. In Lichens of Great Britain and Ireland (Smith, C.W., Aptroot, A., Coppins, B.J., Fletcher, A., Gilbert, O.L., James, P.W. & Wolselsey, P.A. eds): 376-377. London: British Lichen Society. Kauff, F. & Büdel, B. (2005). Ascoma ontogeny and apothecial anatomy in the Gyalectaceae (Ostropales, Ascomycota) support the re-establishment of the Coenogoniaceae. Bryologist 108: 272-281. Lücking, R., Hodkinson, B.P. & Leavitt, S.D. (2016). The 2016 classification of lichenized fungi in the Ascomycota and Basidiomycota – approaching one thousand genera. Bryologist 119: 361-416. Ludwig, L. R. (2014) Coenogonium fruticulosum, a new isidiate species from New Zealand. Australasian Lichenology 75: 18-27 Rivas Plata, E.T.D., Lücking, R., Aptroot, A., Sipman, H.J.M., Umana, L., Chaves, J.L. & Lizano D. (2006). A first assessment of the Ticolichen biodiversity inventory in Costa Rica: the genus Coenogonium (Ostropales: Coenogoniaceae). Fungal Diversity 23: 255-321. Resl, P., Schneider, K., Westberg, M., Printzen, C., Palice, Z., Thor, G., Fryday, A., Mayrhofer, H. & Spribille, T. (2015). Diagnostics for a troubled backbone: testing topological hypotheses of trapelioid lichenized fungi in a large-scale phylogeny of Ostropomycetidae (Lecanoromycetes). Fungal Diversity 73: 239-258.