Thyridium punctulatum (I. Hino & Katum.) R. Sugita & Kaz. Tanaka comb. nov.

Figs 5, 6C

Basionym.

Pleospora punctulata I. Hino & Katum., Icones Fungorum Bamb. Jpn.: 181 (1961).

Holotype.

Japan, Shizuoka, Fuji Bamboo Garden, on dead twigs of Phyllostachys nigra var. henonis, 1 April 1958, K. Katumoto, YAM 21851.

Epitype.

Japan, Yamaguchi, Hagi, Akiragi, near Chikurindoro-park, on dead twigs of Phyllostachys nigra var. nigra, 26 March 2018, K. Tanaka, K. Arayama and R. Sugita, KT 3905 (HHUF 30649 epitype designated here; MBT 10004137), ex-epitype culture MAFF 247510.

Sexual morph.

Stromata scattered to grouped, subepidermal, becoming erumpent to superficial, 0.5-1.2 mm long, 0.2-0.4 mm wide, dark brown. Ascomata perithecial, subglobose to conical, single to 2-3 grouped, 130-190 µm high, 140-230 µm diam., immersed in stromata to erumpent through host surface. Ascomatal wall 7-15 µm thick, composed of 3-5 layers of polygonal, 3-6.5 × 1-4.5 µm, dark brown cells. Ostiolar neck central, cylindrical, 37-85 µm long, 37-63 µm wide, periphysate. Paraphyses numerous, septate, unbranched, cylindrical, hyaline, 77-103 µm long. Asci unitunicate, cylindrical, 67.5-105 × 7.5-11.5 µm (av. 82.9 × 9.4 µm, n = 60), broadly rounded at the apex, with a pronounced non-amyloid apical annulus, short-stalked (3.5-11.5 µm long), with 8 ascospores. Ascospores ellipsoid to oblong, smooth, pale brown, with 3 transverse and 1-2 vertical septa, 10-15 × 5-9 µm (av. 12.8 × 7.0 µm, n = 60), l/w 1.4-2.4 (av. 1.8, n = 60).

Asexual morph (nature).

Not observed.

Asexual morph (culture).

Coelomycetous asexual morph: Conidiomata pycnidial, single to grouped, superficial, globose to subglobose, 100-250 µm high, 170-620 µm diam., composed of polygonal to prismatic, 3.5-7.5 × 2.5-4 µm cells, often becoming cup-shaped when mature, surrounded by setose hyphae. Setose hyphae erect, usually unbranched, septate, up to 225 µm long, 1.5-2.5 µm wide, pale brown. Conidiophores hyaline, thin-walled, simple or irregularly branched, with branches bearing a group of 2-5 phialides terminally. Phialides swollen at the base, tapering at the tip, 7-20 × 1-3 µm, hyaline. Conidia ellipsoidal to obovoid, with a slightly apiculate base, hyaline, smooth-walled, in slimy masses, 2-3.5 × 1-2 µm (av. 2.9 × 1.4 µm, n = 50). Hyphomycetous synasexual morph: Conidiophores micronematous, mononematous, hyaline, thin-walled, simple or irregularly branched, with branches bearing a group of 2-3 phialides terminally. Phialides swollen at the base, tapering at the tip, hyaline, 3-9 × 1-2 µm . Adelophialide absent. Conidia ellipsoidal to allantoid, hyaline, smooth-walled, in slimy heads, 2.5-8 × 1-3 µm (av. 4.3 × 1.6 µm, n = 87). Chlamydospores rarely present, solitary or chained, 4-5.5 µm diam., hyaline to pale brown.

Culture characteristics.

Colonies on MEA at 25 °C attained 31-32 mm diam. after a week in the dark, granulose, whitish. On OA attained 38-39 mm diam., granulose, whitish. On PDA attained 35-36 mm diam., whitish to buff (45) (Fig. 6C).

Other specimen examined.

Japan, Iwate, Morioka, Ueda, Campus of Iwate University, on dead culms of Phyllostachys pubescens, 17 February 2003, K. Tanaka and Y. Harada, KT 1015 (HHUF 29350), living culture JCM 13159 = MAFF 239669.

Notes.

This species has been described from Phyllostachys nigra var. henonis, as a species of Pleospora ( Dothideomycetes; Hino 1961). Our phylogenetic analysis (Fig. 1) shows that this species is a member of the genus Thyridium ( Sordariomycetes). The morphological features of this species are consistent with those of the genus Thyridium, including immersed to erumpent, single to grouped, perithecial ascomata with a cylindrical ostiolar neck, unitunicate asci and muriform, pigmented ascospores (Eriksson and Yue 1989). Therefore, we propose a new combination, T. punctulatum, for Pleospora punctulata .