Dendrostoma leiphaemia (Fr.: Fr.) Senan. & K.D. Hyde, in Senanayake et al., Fungal Diversity 93: 317 (2018).

Jaklitsch, Walter M. & Voglmayr, Hermann, 2019, European species of Dendrostoma (Diaporthales), MycoKeys 59, pp. 1-26 : 1

Dendrostoma leiphaemia (Fr.: Fr.) Senan. & K.D. Hyde, in Senanayake et al., Fungal Diversity 93: 317 (2018). Figure 9

Sphaeria leiphaemia Fr., Syst. mycol. (Lundae) 2(2): 399 (1823) (Basionym).

≡ Amphiporthe leiphaemia (Fr.) Butin, Sydowia 33: 22 (1980).

≡ Diaporthe leiphaemia (Fr.: Fr.) Sacc. [as ‘leiphaema’], Atti Soc. Veneto-Trent. Sci. Nat. 2(1): 135 (1873).

≡ Valsa leiphaemia (Fr.) Fr., Summa veg. Scand., Sectio Post. (Stockholm): 412 (1849).

Diagnosis.

Dendrostoma leiphaemia is recognized by conspicuous ectostromatic discs, broad conical ostiolar necks, and broad multiguttulate ascospores.

Description.

Sexual morph: pseudostromata 1-5 mm in their widest dimension in cross section, pulvinate to conical, circular, elliptic or irregular in outline, scattered, aggregated to confluent, sometimes forming lines of up to 15 mm length, causing conspicuous bumps and lesions in the bark; dark brown dorsal zones present within the bark, absent in basal regions. Ectostromatic discs 0.35-2.5 mm in their widest dimension, conspicuous, whitish, cream, pale brown, pale yellowish brown to dull brown, fusoid, triangular to circular in section, flat or convex, often surrounded by bark flaps, elevated up to 1.3 mm beyond the bark surface, brittle to powdery, first present as a covering layer with ostiolar necks subsequently bursting through it, eventually crumbling away. Ostioles 1-30 per disc, (88 –)124–220(– 336) µm (n = 64) in diameter, dark brown, black, or reddish brown with black, rarely yellowish tip, cylindrical with conical apical part, attenuated to 35 –90(– 180) µm at the rounded, compressed or coarsely sulcate tip, projecting to 250, less commonly 400 µm, white, in upper regions sometimes yellow inside, periphysate, arising centrally to eccentrically from the perithecial venter and slightly convergent above perithecia; turning partly yellow, partly brown in 3% KOH. Entostroma whitish to pale yellowish or pale bark-coloured, prosenchymatous to pseudoparenchymatous, the latter particularly in the vicinity of perithecia, consisting of 1.5-5 µm wide hyphae or angular cells, mixed with bark cells. Perithecia arranged in valsoid configuration, tightly aggregated, (292 –)380–625(– 700) µm (n = 21) in diameter, globose to depressed-subglobose, with gelatinous contents, collapsing upward; peridium ca 7-35 µm thick, pale olivaceous to dark brown, consisting of an outer layer of isodiametric to elongate, thick-walled dark brown cells and an inner layer of compressed elongate, hyaline to brownish, thin-walled cells (5 –)6.5–16(– 22.5) µm (n = 31). Paraphyses absent at maturity. Asci floating freely in the centre when mature, (49 –)58–71(– 80) × (9 –)10–13.5(– 17.5) µm (n = 56), clavate, oblong, fusoid to subellipsoid, with a refractive apical ring, containing 8 bi- to triseriate, fasciculate or obliquely uniseriate ascospores. Ascospores (15 –)16–19(– 21) × (3.8 –)4.3–5.2(– 5.8) µm, l/w (2.7 –)3.3–4.1(– 4.7) (n = 95), 2-celled, not or slightly constricted at the median or slightly eccentric septum, inequilaterally ellipsoid or oblong, straight or curved, with the upper cell sometimes slightly wider than the lower, hyaline, multiguttulate, smooth, lacking appendages.

Asexual morph co-occurring with the sexual morph, acervular, either present as locules in lateral regions of pseudostromata above perithecia or forming separate, conical to pulvinate, dorsally blackened acervuli 0.9-2.2 mm in diameter, with conical upper part or whitish to cream or brownish, more-or-less circular, continous or deeply fissured discs ca 0.4-1 mm in diameter and whitish-cream, partly hollow interior containing slightly darker fertile chambers meandering through it. Walls and interior consisting of brown or hyaline to pale yellowish brown textura angularis. Phialides lining inner wall of the cavity, sessile, (4.8 –)6.5–11(– 12.7) × (1.7 –)2–3.8(– 5.3) µm (n = 16), subcylindrical to lageniform, reddish brown in 3% KOH (when old). Conidia (4.8 –)7–9.5(– 11) × (1.5 –)1.8–2.3(– 2.5) µm, l/w (2.3 –)3.3–4.9(– 6.3) (n = 50), unicellular, cylindrical, oblong, subclavate, rhomboid or narrowly ellipsoid, straight to slightly curved, often with a truncate or acute end, hyaline, turning pinkish-yellowish in 3% KOH, smooth, with minute terminal drops, adhering together in masses when old.

Culture characteristics.

On CMD at 16 °C in the dark, colony irregular or dimorphic, dense, white, partly covered by short white aerial hyphae, zonate, soon turning dark brown to black with red or reddish brown spots, reverse dark brown, reddish brown with white, pale apricot or reddish brown spots and margins.

Specimens examined.

AUSTRIA, Kärnten, St. Margareten im Rosental, shrubs in front of the Stariwald, grid square 9452/4, on branches of Quercus petraea , 9 Jan. 1995, W. Jaklitsch W.J. 443 (WU 37034); same area, 31 Dec. 1997, W. Jaklitsch W.J. 1122 (WU 37035); Niederösterreich, Hagenbrunn, Bisamberg east side, grid square 7664/3, on twigs of Quercus petraea , 30 Oct. 1999, W. Jaklitsch W.J. 1396 (WU 37036); Mannersdorf am Leithagebirge, on twigs of Quercus petraea , 12 Mar. 2016, H. Voglmayr (specimen lost); Mühlleiten, Herrnau, on branches of Quercus petraea , 29 Mar. 2015, H. Voglmayr (WU 37037; culture CBS 145800 = D105); Oberösterreich, Unterach am Attersee, Stockwinkl, Egelsee, grid square 8147/3, on branch of Quercus petraea , 25 May 1996, W. Jaklitsch W.J. 880 (WU 37038); Steiermark, Wundschuh, Kaiserwald, at the Seerestaurant, grid square 9058/4, on branch of Quercus petraea , 10 Sep. 2002, W. Jaklitsch W.J. 1936 (BPI 843342; culture A.R. 3874); Vienna, 19th district, at the Cobenzl, grid square 7763/2, on branches of Quercus cerris , 11 Feb 1995, W. Jaklitsch W.J. 482 (WU 37039); same area and host, 27 Feb. 1999, W. Jaklitsch W.J. 1286 (WU 37040). POLAND, E Grajewo, Kuligi, on branches of Quercus robur , 28 July 2015, H. Voglmayr (WU 37041; culture D144).

Notes.

Asexual fructifications of this species are reported to have dimorphic conidia ( Butin 1980; Wehmeyer 1933). However, for the description above only overmature material with a single type of conidia was available, the measurements of which agree with the cylindrical form given as 7-12 × 1.5-2 µm by Wehmeyer (1933), but their shape is more variable, possibly due to their age. As Butin (1980) observed, the asexual morph precedes the sexual morph and may still be present as separate acervuli among sexual pseudostromata or as locules within the periphery of the latter.

Figures

Figure 9. Dendrostoma leiphaemia. a-s Sexual morph a-e ectostromatic discs and ostioles f pseudostroma in cross section g pseudostroma in vertical section h peridium in cross section i, n-s ascospores j-m asci t-z asexual morph t conidioma in cross section u, v phialides w-z conidia; a, d-g, t-z WU 37037 (D 105), b WU 37036 c, h, j, k, n WU 37038 i, l, m, p-s Mannersdorf o WU 37040. h, j, k, n, o, u-z In 3 % KOH. Scale bars: 500 µm (a-g, t), 20 µm (h), 10 µm (j-m), 5 µm (i, n-s, u), 3 µm (v-z).