Sclerencoelia fascicularis
Sclerencoelia fascicularis (Alb. & Schwein.) Pärtel & Baral, IF: 815440
Basionym: Peziza fascicularis Alb. & Schwein.,
Conspectus Fungorum in Lusatiae superioris (Leipzig): 315, tab. XII Fig. 2 (von Albertini and von Schweinitz 1805).
≡ Phibalis fascicularis (Alb. & Schwein.) Wallr., Flora Cryptogamica Germaniae 2: 445 (1833).
≡ Encoelia fascicularis (Alb.&Schwein.) P. Karst., Bidrag till Kännedom av. Finlands Natur och Folk 19: 217 (Karsten1871).
≡ Cenangium fasciculare (Alb. & Schwein.) Quél., Mémoires de la Société d’Émulation de Montbéliard 5: 415(1873).
= Peziza populnea Pers., Syn. meth. Fung. (Göttingen) 2: 671 (Persoon 1801).
≡ Encoelia populnea (Pers.) J. Schröt., Krypt.-Fl. Schlesien (Breslau) 3.2(7): 140 (1893).
≡ Cenangium populneum (Pers.) Rehm, inWinter, Rabenh. Krypt.-Fl., Edn 2 (Leipzig) 1.3(lief. 31): 220 (1889) [1896].
= Dermea ("Dermatea") fascicularis forma carpini Rehm in Voss, Verh. Zool.-Bot. Ges. Österreich 37: 223 (1887).
≡ Cenangium carpini Rehm, Discom. Rabenhorst’s Kryptogamen–Flora, Pilze – Ascomyceten 1(3): 221 (1889).
≡ Encoelia carpini (Rehm) Boud., Histoire et Classification des Discomycètes d’Europe: 161 (1907).
Holotype absent. Neotype TU 104531 designated here, INSD accession number MBT204575.
Sclerotia developing within or beneath the bark, usually flattened button-shaped. Apothecia erumpent, 1–6 in a cluster, sometimes in rows along bark splits, sessile to substipitate, cupulate, 2–10(−14) mm in diam. (mainly 3–6 mm), 400–700 μm thick at lower flanks, 200 μm near margin; disc dark fawn- to umber-brown, olivaceous-grey or brownish black, margin finely rough or crenulate, not rarely incised, dark reddish-brown, ± densely covered by white to pale cream pruina, outside greyish- to brownish black, scattered whitishpruinose; black when dry. Ectal excipulum 50–70 μm thick at base, 20–30(−40) μm at lower flanks and towards margin, inner part of vertically oriented t. globulosa-angularisprismatica, cortical cells broadly ellipsoid to globose, *thinwalled, † thick-walled, 6–10 μm in diam., with grey-brown
(in KOH olivaceous) exudate especially towards the cortex; marginal cells cylindrical, forming free protruding elements, covered by rough, olive-brown exudate, septate, 3.5–6.5 μm wide, apically rounded, uninflated or slightly clavate. Medullary excipulum 400–600 μm thick in centre, 80–100 μm at lower flanks, of dense or loose t. intricata, nongelatinized, hyaline or with brownish hue (in KOH olivaceous), hyphae 2–5 μm wide, slightly rough, light olive towards ectal and medullary excipulum. Subhymenium light brown (in KOH olive) of small-celled, dense t. intricata. Asci cylindric-clavate, apex truncate-rounded with †1–2.5 μm thick apical wall (mature 1–1.5 μm), inamyloid {3} or faintly blue {9} in upper part of wall in MLZ or IKI (especially when KOH-pretreated), *100–130(−140) × (8.5–)10–12(−12.5) μm{5}, †(80–)88–100 × (6–)6.7–8.3 μm{6}, pars sporifera *30–40 μm, arising from croziers {7}. Ascospores cylindric-allantoid, slightly to moderately curved, *(12–)13–15.5(−17) × (3.2–)3.5–4.2(−4.7) μm {5}, †10.6–15.3 × 3–
3.8(−4.2) μm {7}, aseptate, but sometimes one-septate during germination, sometimes forming globose microconidia directly or on short germ tubes at one or both ends, *2.2–3 × 2–2.5 μm diam., with 1–2 oil drops. Paraphyses apically uninflated to slightly clavate, fusoid, or moniliform, sometimes with apical outgrowths, */†3–5.5(−6.5) μm wide, the upper part hyaline or pale to bright brown, surrounded by brown exudate, slightly roughened to densely covered with light to dark brown granules. Crystals 4–12 μm in diam., abundant, especially on outer surface of the receptacle, some also on hymenium, in some specimens forming abundant 12–32 μm large subglobose druses in ectal excipulum.
Habitat: on dead bark and wood of 1–50 cm thick, corticated, detached branches and fallen logs of Populus tremula, P. tremuloides, P. grandidentata, P. balsamifera, rarely P. × canadensis, lying on the ground more or less covered by litter, sometimes up to 0.5 m above ground. Phenology: Oct–Jun.
Distribution: common in temperate and hemiboreal Europe and North America (Seaver 1951; Groves and Elliott 1971, Torkelsen and Eckblad 1977, Breitenbach and Kränzlin 1984, Hansen and Knudsen 2000).
Comments: Typically, apothecia of this species form clusters, unlike in other species of the genus. Often rhizomorphlike structures, referable to sclerotia, are observed in the substrate in or under the bark. The ascospores and asci remain viable in dried specimens for nearly three months. Most commonly the apothecia form when the host is blooming, a phenomenon also characteristic of some other taxa in the Sclerotiniaceae, members of which are mainly parasites of various plants (Kirk et al. 2008). The amount of crystals varied among the studied samples, and only in H.B. 3424 were they seen to form abundant large druses in the ectal excipulum. The ascus amyloidity is better visible after KOH-pretreatment but even in that case the reaction of the apical ring is faint, infrequently seen only in some of the asci. Encoelia carpini (Rehm) Boud. closely resembles Sclerencoelia fascicularis in erumpent apothecia growing in dense roundish fascicles of up to 12 fruitbodies. Because we detected no morphological differences between the type material in S and specimens of S. fascicularis on Populus, we consider E. carpini a synonym of S. fascicularis. The taxon was described from dead, dry, corticated twigs and branches of Carpinus betulus (von Voss 1887, Rehm1889). The holotype contains only bark, which did not permit us to confirm the host identity. The ITS sequence from a collection from Telemark (Norway), reported on Corylus avellana under the name E. fascicularis (Holst-Jensen et al. 1997), is almost identical to ITS sequences obtained from apothecia growing on Populus. Persoon (1801), and von Albertini and von Schweinitz (1805) described the same fungus under different names using collections of Populus tremula (unlocalized, and Niesky, Eastern Saxony, Germany, respectively). Saccardo (1889: 565) accepted Cenangium populneum (Pers.) Rehm as the valid name by placing Peziza fascicularis Alb. et Schwein. in synonymy. However, Fries (1822: 75) reversed this scheme by placing Peziza populnea Pers. in synonymy of Peziza fascicularis Alb. et Schwein. Herewith, Fries sanctioned the name P. fascicularis over the older populnea (Art. 13 ICN). Persoon reported caespitose (= fasciculate), cupulate, grey apothecia while Albertini & Schweinitz described these to grow by 6–12 fruitbodies, almost tightly caespitose, internally dirty olivaceous, black outside. The latter authors distinguished a "Var. ß" on Salix and Fraxinus, with entirely black apothecia growing subsolitary or in small fascicles, which appears to refer at least in part to Sclerencoelia fraxinicola. Herbarium material of Albertini has generally not been preserved. Therefore, in order to stabilize nomenclature in this group, we designate the neotype of Sclerencoelia fascicularis.
Apothecia-derived ITS sequences from three collections formed a group together with a sequence from an endophyte from needles of P. sylvestris.
Type specimens examined: ESTONIA, Saaremaa, Lümanda Comm.,Viidumäe Nature Reserve, 58.2687°N 22.1298°E, alt. 50 m, Populus tremula, on bark of a fallen trunk; 19 Apr 2015, V. Liiv (TU 104531), neotype, KL401.
Specimens examined: ESTONIA, Jõgevamaa, Puurmani Comm., Pikknurme, Laanesaare, P. tremula, on bark of felled trunks, 17 Apr 1969, K. Kalamees (TAAM 77702); Lääne-Virumaa, Laekvere Comm., Luusika, Hanguse, 58.9833°N 26.6167°E, alt. 90 m, P. tremula, on bark of a branch, 14 May 1970, K. Kalamees (TAAM 78467); Tartumaa, Meeksi Comm., Järvselja Nature Reserve, forestry sq. 226, 58.2813°N, 27.3261 °E, alt. 50 m, P. tremula, on bark, 24 May 1970, K. Kalamees (TAAM 198296); Tartu Comm., 2 km N of Väägvere, 58.483°N 26.839°E, alt. 48 m, in wet Populus mixed forest, P. tremula, on corticated branches, 15 Apr 1982, K. Kalamees (TAAM 122302); Tartu Comm., Muri, near parking place of Lake Vasula, 58.4302°N 26.7232°E, alt. 54 m, in mixed forest with Betula and Populus, on bark of P. tremula, on a fallen trunk in snow, 9 Apr 1966, K. Kalamees (TAAM 76013); Tähtvere Comm., Vorbuse, 58.435°N 26.652°E, alt. 44 m, swampy mixed birch forest, P. tremula, on fallen log, 12 Apr 1959, A. Raitviir (TAAM 200564, KL144). GERMANY, Saarland, Lebach, Steinbach, Seiterswald, 49.46°N 6.95°E, alt. 370 m, P. tremula, on a dead standing branch, 23 May 2010, D. Gerstner (TU 104508, KL347); Thüringen, 3 km NW of Sonneberg, 1.8 km N of Bettelhecken, Wehd, 50.382°N 11.1445°E, alt. 480 m, branch of P. tremula, on bark, 10 Mar 2012, I. Wagner (ø); 2.8 km SWof Sonneberg, 1 km N Fungal Diversity (2017) 82:183–219 199 of Ebersdorf, Oberlinder Müß, 50.338°N 11.151°E, alt. 353 m, branch of P. tremula, on bark, 2 Apr 2011, I. Wagner (I.W. 110,402); Baden-Württemberg, 7.5 km NW of Stuttgart, 1.3 km W of Weilimdorf, Fasanenwald, 48.812° N 9.095°E, alt. 340 m, branch of P. x canadensis, on bark, 10 Dec 1977, H.O. Baral (H.B. 2221); ibid., 16 Dec 1977, O. Baral & H.O. Baral (H.B. 2232); ibid., 25 Oct 1992, H.O. Baral & E. Weber
(H.B. 4798). LUXEMBOURG, Gutland, 6 km SW of Ettelbruck, 1 km SE of Michelbouch, Biischtert, Haerenhecken, 49.814°N 6.033°E, alt. 360 m, branch of P. tremula, on wood, 30 Apr 1988, G. Marson (G.M., 3696, H.B. 3424). FRANCE, Champagne-Ardenne, Dépt. Marne, Brie, 14 km Wof Sézanne, 2.3 km WSW of Esternay, Bois de Nogentel, 48.722°N 3.531°E, alt. 185 m, branch & trunk of P. tremula, on bark, 15 May 1993, H.O. Baral & G. Marson (G.M.). ITALY: Trentino–Alto Adige, Südtirol, 18 km SSW of Bozen, NNE of Montagne, 46.336°N 11.3085°E, alt. 600 m, branch of P. tremula, on bark, 13 Apr 1979, A. Bollmann (H.B. 2542). SLOVENIA, Ulrichsberg near Krainburg, ‘Carpinus betulus’ (perhaps Populus, only bark present), on bark, 6 Mar 1886, W. Voss, holotype of Dermatea fascicularis forma carpini Rehm (S-F73569).