A new species of Stamnaria (Leotiomycetes, Helotiales) from Western Siberia Author Haelewaters, Danny Author Filippova, Nina V. Author Baral, Hans-Otto text MycoKeys 2018 32 49 63 http://dx.doi.org/10.3897/mycokeys.32.23277 journal article http://dx.doi.org/10.3897/mycokeys.32.23277 1314-4049-32-49 Stamnaria yugrana Filippova, Haelew. & Baral sp. nov. Diagnosis. Characterised by the presence of both lanceolate and cylindrical paraphyses, fusoid-clavate ascospores with a length/width ratio of predominantly>4 and free-ending hyphae at the inner excipulum of the tube-shaped, even collar. Saprophytic on dead branches of E. sylvaticum . Figure 1. Study site of Stamnaria yugrana growing on litter of Equisetum sylvaticum in Western Siberia near the Khanty-Mansiysk town. Types. Holotype: Russia, Western Siberia, Khanty-Mansi Autonomous Okrug - Yugra, 25 km ENE of Khanty-Mansiysk town, 1.2 km SSE of Shapsha village, 61.07929"N, 69.46925"E, alt. 40 m, 9 Jun 2012, leg. N.V. Filippova, on fallen side branches of Equisetum sylvaticum L. lying amongst other forest litter in a mixed coniferous-deciduous forest; Biological Collection of Yugra State University (YSU-F-03519). Isotypes: LE-295215; FH 01146308. Paratypes: ibid., 16 Jun 2008 (YSU-F-00097, material lost; LE-295060); ibid., 22 Feb 2014, substrate collected from under snow and grown in a moist chamber (YSU-F-04933); ibid., 25 Feb 2015 (YSU-F-06579; LE-296061). Figure 2. Apothecia of Stamnaria yugrana on side branches of Equisetum sylvaticum : A Apothecia grown in situ under well-lit conditions B Apothecia grown in shady conditions after incubation in a moist chamber C Median section through an apothecium after incubation in a moist chamber (dead, in CR). A from YSU-F-03519, B from YSU-F-04933, C from YSU-F00097. Scale bars: A 1.0 mm, B, C 0.5 mm. Description. Apothecia urn-shaped, stipitate, 0.25-0.6 mm in diameter when mature, 0.5-1 mm high, varying depending on light conditions, being stouter with shorter stipe when substrate exposed to sunlight; receptacle light yellow(-ochraceous) when fresh, with even, whitish collar ~80-120 µm high, stipe pale yellowish-translucent, 100-380 x 130-300 µm , receptacle becoming light brown on drying; scattered to moderately gregarious, often abundant on the branches. Ectal excipulum outer layer *40-45 µm thick at middle flanks and margin, made up of strongly gelatinous tissue of loose, parallel to wavy hyphae 2-3 μm broad, septate, embedded in abundant gelatinous matrix (textura oblita); inner layer *~45 µm thick at middle flanks, made up of textura prismatica-porrecta running parallel to outside, cells at middle flanks *17-44 x 7-12 μm , slightly narrower in the collar region, much narrower in stipe (*20-45 x 3-5 µm ); the inner layer of the collar composed of narrow hyphae, free upper part of these hyphae internally covered by lateral cellular outgrowths *2-5 x 1.5-2 µm . Medullary excipulum well developed, of dense, parallel, septate hyphae (textura porrecta) without gel, cells *65-90 x 2.5-6 (-7.7) μm ; subhymenium well developed (*20-30 thick), of intricate hyphae *2 μm broad. Asci cylindrical, developing from croziers which are difficult to see in mature asci, with apical thickening enclosing a hemiamyloid ring of Calycina-type (rb: dirty red at high, blue at low concentration), *146 x 12.5 [123-159 (-206) x 11.7-13.5] μm , †98 x 9 (90-110 x 8-10.5) μm , 8-spored, spores *obliquely biseriate. Paraphyses of two types: (1) lanceolate, exceeding asci for *12-20 µm when young and *30-40 μm when fully developed, septate in lower part, non-septate in broad upper part, with quite acute tip, in young paraphyses with granular (multiguttulate) vacuolar content of moderate refractivity (VBs), later replaced by larger non-refractive vacuoles, *5-7 (†3-6) μm broad in upper part; (2) cylindrical, more abundant, not exceeding the asci, *2.3-3 μm broad above, septate, with obtuse tip, rarely branched below and scarcely enlarged in upper segment, without VBs, with pale yellow-orange pigment in middle and lower part. Ascospores fusoid-clavate, slightly to distinctly heteropolar, with rounded to obtuse ends, usually without any gel around, filled with granular oil content in both halves, leaving a central zone for the single nucleus, variable in length, *19.8 x 4.8 (16.5-24.5 x 4.2-5.6), n=18, Q=4.1 (YSU-F-04933); †20.5 x 4.0 (17.2-24.2 x 3.6-4.6) μm , n=37, Q=5.1 (YSU-F-03519, YSU-F-04933). Figure 3. A1 Young living paraphysis with multiguttulate, medium refractive vacuolar content (VBs), A2 Mature living paraphysis with large non-refractive vacuoles A3 Dead paraphysis with small oil drops (LBs), vacuoles disappeared B Paraphyses of cylindrical and lanceolate type C Mature living asci D Mature ejected ascospores with granular lipid content of minute LBs (confluent in dead state) E Ascus bases with croziers F Apices of mature and immature ascus (stained in IKI). All * and F from YSU-F-04933, all other † from YSU-F-00097. Scale bars: A, D, E, F 10 μm , B, C 20 μm . Etymology. Referring to Yugra, the historical name of the region (currently "Khanty-Mansi Autonomous Okrug - Yugra"). Distribution. Known only from the type locality.