Orbilia xanthoguttulata Baral, 2014

Quijada, Luis, Baral, Hans-Otto, Jaen-Molina, Ruth, Weiss, Michael, Castells, Juli Caujapé- & Beltrán-Tejera, Esperanza, 2014, Phylogenetic and morphological circumscription of the Orbilia aurantiorubra group, Phytotaxa 175 (1), pp. 1-18 : 12-13

Orbilia xanthoguttulata Baral , spec. nov. (Fig. 7) MycoBank MB 492257

Differt ab Orbilia aurantiorubra apotheciis plerumque vivide aureo-luteis, etiam ochraceo-aurantiacis, paraphysibus spathulatis, cellulis vivis terminalibus paraphysium et excipuli plerumque guttulas luteas oleosas continentibus, sine refractivis corpusculis solubilibus non globosis, margine saepe processis vitreis brevibus praedito, corpusculis refringentibus ascosporarum brevioribus. Habitat ad corticem, raro lignum, ramorum siccorum arborum angiospermarum, raro coniferarum, in zona temperata humida in Europa.

Type:— EUROPE. SPAIN. Asturias: on Genista cf. florida , 1625 m, 30 October 1991, A. Raitviir and R. Galán 6796 (holotype AH!, isotype herb. Baral!) .

Apothecia rehydrated (0.2–)0.3–1(–1.5) mm diam., 0.19–0.31 mm high (receptacle 0.11–0.15(–0.22) mm), pale to light cream-yellowish or mostly golden yellow, also ochraceous-orange, sometimes turning deep orange to bloodred with age, somewhat translucent, round, lobate when large, scattered to gregarious; disc slightly concave to flat, margin ± thick, 0–15 µm protruding, smooth; often with a distinct, cylindrical to obconical stipe 0.05–0.2(–0.3) × 0.2–0.4(–0.8) mm, superficial or slightly erumpent from bast; dry light to deep honey-yellow-ochre to yellow-orange, orange-apricot-red, or vermilion-red. Asci *(47–)53–74(–82) × (4–)4.2–5(–5.3) µm {10} → 5.7–5.8 µm wide, †(40–)44–67(–79) × (3.5–)3.8–4.6(–5) µm {7}, 8-spored, spores *4-seriate, ± helicoidally twisted, (2–)3–5(–6) lower spores inverted {14} (not or rarely mixed), pars sporifera *23–30(–35) {8} or *30–36(–39) µm {1} long, †20–30 or 30–40 µm; apex (†) strongly truncate. Ascospores *(10–)11–14.5(–16) × (1.2–)1.3–1.6(–1.8) µm {17}, †(9.2–)11–14.5 × 1– 1.5 µm {6}, narrowly fusiform with (sub-)cylindrical middle part, apex acute (to acuminate), base slightly to strongly attenuated, falcate to mostly distinctly helicoid, medium to strongly curved especially near base; SBs *(1.8–)2–3(– 3.3) × 0.7–1.3 µm {16}, tear-shaped. Paraphyses apically (slightly to) medium or strongly inflated, spathulate (to sublageniform), terminal cells *11–31 × (2.5–)3–4.5(–5.7) µm {9}, †2.5–4.2 µm wide {2}, covered by glassy caps of exudates, exceeding the living or dead asci by 2–8 µm, lower cells *9–15 × 1.3–2.1 µm {4}, †1–1.7 µm wide {3}; never branched at upper septum; hymenium (pale to) light to bright yellow due to abundant yellow LBs. Medullary excipulum hyaline, 20–70 µm thick, sometimes up to 150 µm in centre, of medium loose to dense textura intricata with many inflated cells, very sharply delimited from ectal excipulum by a parallel 10–20(–30) µm thick layer of dense or loose t. porrecta. Ectal excipulum hyaline, towards margin usually light to bright yellow-orange, of thin-walled, vertically oriented t. globulosa–angularis–prismatica, 50–100(–180) µm thick at base, 30–100 µm at lower flanks, cells *10–25(–28) × 6–17(–20) µm {7}; 15–30 µm thick at mid flanks and margin, at margin of t. angularis–globulosa oriented at a 70–90° angle {8}, marginal cortical cells clavate to subglobose, *(4–)7–11(–14) × (3–)4–6(–9) µm {5}; glassy processes present {13}, (0–)1–5(–9) × 3–5(–7) µm, conical, low to high refractive, partly stratified, hyaline to pale yellowish, ± curved outwards if not very short, also ± absent {4}, often difficult to distinguish from exudate. LBs bright to deep golden yellow(-orange), near apex and in lower half of paraphyses 0.2–1(–2) µm diam., scattered or mostly rather abundant {>18}; in medullary excipulum 1–2.5 µm diam., sparse; in ectal excipulum scattered or abundant, small to large; deep blue-green-olive when applying IKI to water mount. Exudate over paraphyses forming individual, conical to convex or truncate glassy caps on nearly all apices, (0.3–)0.5–2 µm thick {>18}, smooth to warted, firmly attached, hyaline, over margin and flanks 0.2–0.5 µm thick.

Etymology:— Named according to the yellow lipid bodies in the paraphyses and marginal excipular cells.

Distribution and ecology:— From atlantic W- and subatlantic to subcontinental Central and boreal N-Europe, comprising planar or colline to subalpine, partly thermophilous forests at 4–1755 m altitude, with some records from oro- to Mediterranean Maquis in S- and SW-Europe, showing a remarkably diverse ecological amplitude, on gymno- and angiosperms, on slightly to strongly decayed bark, rarely on wood. Phenology: I–XII. Desiccation tolerance: some immature asci still viable after 4 months (Central Europe), some mature asci and excipular cells still alive after 31 months ( Spain).

Other material examined:— EUROPE. FRANCE. Loire: on Fraxinus excelsior , 880 m, 6 May 2010, P. Chaillet (herb. Baral 9291!); Deux-Sèvres: on Ulmus sp. , 135 m, 1 May 2006, B. Coué (herb. Baral 8170!); Savoie: on Salix sp., 1550 m , 6 May 2005, N. van Vooren (herb. Baral 7915b!); Drôme: on Cercis siliquastrum , 383 m, 12 September 2009, G. Marson (herb. Baral 9182!). GERMANY. Bayern: Oberbayern, on Picea abies, 1200 m , 30 September 1999, R. Kirschner (herb. Baral 6510!); Brandenburg: on Quercus robur , 55 m, 24 November 2007, R.K. Schumacher (herb. Baral 8698!). LUXEMBOURG. L’Oesling: on cf. Populus tremula , 310 m, 26 March 2001, G. Marson (herb. Baral 6989a!); ibid., 26 April 1994, G. Marson (herb. Baral 5065!); Gutland: on Fagus sylvatica , 350 m, 21 August 2005, G. Marson (herb. Baral 7884!). SPAIN. Andalucía: on Salix atrocinerea , 663 m, 6 January 2004, F. Prieto and A. González (herb. Baral 7464!). SWEDEN. Hälsingland: on Populus tremula , 18 m, 23 July 2010, H.O. Baral and P. Perz (herb. Baral 9366!); Skåne: on Ulmus glabra , 135 m, 3 June 2006, T. Laessøe and H.O. Baral (herb. Baral 8208b!). SWITZERLAND. Glarus: on Picea abies, 1100 m , 6 September 1995, R. Kirschner (herb. Baral 5330!).

FIGURE. Morphological characteristics of Orbilia xanthoguttulata . 1. Drawing with vital characteristics for the isotype (H.B. 5092). 2. Apothecia on natural substrates, scale bars 2a–h= 500 µm. 3. Living and dead ascospores, scale bars 3a–g= 10 µm. 4. Section of apothecia, 4a at flanks, 4b at margin, with glassy processes, scale bars 4a–b= 10 µm, 4c= 50 µm. 5. Paraphyses. 6. Asci; scale bars 5a–d and 6a–d= 10 µm. (H.B. 6989a= 2a, 3d, 6a; H.B. 7464= 2b, 3g, 4a, 5d; H.B. 7915b= 2e, 3f, 4b; H.B. 8170= 2g, H.B. 8208= 2d, 3b, 4c, 5b, 6d; H.B.

8698= 2c, 3c, 5c, 6b; H.B. 9182= 2f; H.B. 9291= 2h, 3a, 5a, 6c).