Coryneum songshanense C.M. Tian & N. Jiang

Jiang, Ning, Voglmayr, Hermann & Tian, Cheng-Ming, 2019, Morphology and phylogeny reveal two novel Coryneum species from China, MycoKeys 56, pp. 67-80 : 67

Coryneum songshanense C.M. Tian & N. Jiang sp. nov. Figure 3

Diagnosis.

Coryneum songshanense can be distinguished from the morphologically similar C. sinense by its narrower conidia.

Holotype.

CHINA. Beijing City: Songshan Mountain, on dead twigs of Quercus dentata , 15 June 2018, N. Jiang & C.M. Tian (holotype: BJFC-S1722; ex-type culture from ascospore: CFCC 52997).

Etymology.

Named after the mountain on which it was collected, Songshan Mountain.

Description.

Associated with canker on twigs of Quercus dentata . Sexual morph: Pseudostromata 0.3-1 mm diam., typically distinct, circular, without perithecial bumps, containing up to 6 perithecia embedded in a well-developed entostroma. Ectostromatic disc distinct, circular, black, 0.3-0.5 mm diam. Central column and entostroma grey. Ostioles inconspicuous and often invisible at the surface of the ectostromatic disc. Perithecia (150 –)200–450(– 550) μm diam. (n = 20), globular, somewhat flattened at the base with black short neck. Asci 75-145 × 17-23 μm, 8-spored, unitunicate, clavate, shortly pedicellate, apically rounded, with an inconspicuous apical ring. Ascospores (24.1 –)25.5–35.4(– 38.2) × (7.5 –)7.9–9.8(– 10.6) μm, l/w = (3.0 –)3.3–3.8(– 4.2) (n = 50), 2-seriate, fusiform, ends pointed, uniseptate or aseptate, not constricted at the septa, hyaline, guttulate, smooth-walled. Asexual morph: Conidiomata acervular, 0.2-0.6 mm wide, 0.2-0.5 mm high, solitary, erumpent through the outer periderm layers of the host, scattered, surface tissues above slightly domed. Conidiophores 15-35 μm long, 4-7 μm wide, unbranched, cylindrical, septate, hyaline at the apex, pale brown at the base. Conidiogenous cells holoblastic, integrated, indeterminate, cylindrical, expanding towards the apices, pale brown, smooth, with 0-1 percurrent extensions. Conidia (51 –)56–67(– 76) × (9 –)10–11(– 11.5) μm, l/w = (5.2 –)5.5–6.9(– 8.1) (n = 50), variable in shape, curved, broadly fusiform to fusiform, cylindrical or clavate, dark brown, smooth-walled, 5-7-distoseptate, apical cell with a hyaline tip, truncate and black at the base.

Culture characters.

On PDA at 25 °C, colonies growing slowly and unevenly, reaching 70 mm diam. within 30 d, gradually becoming brownish dark grey in colour with scant cottony aerial mycelium, asexual morphs developed after 40 d.

Additional specimen examined.

CHINA. Beijing City: Songshan Mountain, on dead twigs of Quercus dentata , 15 June 2018, N. Jiang & C.M. Tian (isotype: BJFC-S1723; living culture from conidium: CFCC 52998).

Notes.

So far, ten species and one variety have been described from Quercus branches, and they can be distinguished by conidial characteristics ( Muthumary and Sutton 1986, Jiang et al. 2018, Table 1). Coryneum songshanense and C. sinense can be distinguished from C. arausiacum , C. depressum , C. elevatum , C. japonicum , C. megaspermum , C. megaspermum var. cylindricum , C. neesii , C. umbonatum , and C. quercinum by unbranched conidiophores ( Sutton 1975, Muthumary and Sutton 1986, Jiang et al. 2018). Coryneum songshanense is obviously distinguished from C. sinense in narrower conidia (9-11.5 μm in Coryneum songshanense vs. 13-17 μm in C. sinense ) and phylogeny ( Fig. 1 ).

Figures

Figure 1. Phylogenetic tree based on an MP analysis of a combined DNA dataset of ITS, LSU, TEF 1 - α and RPB 2 gene sequences for the species of Coryneum. Bootstrap values ≥ 50 % for MP / ML analyses are presented at the branches. Scale bar = 50 nucleotide substitutions.

Figure 3. Coryneum songshanense from Quercus dentata (BJFC-S 1722, holotype) A, B Fruiting bodies on natural substrate in surface view C pseudostroma in transverse section, showing perithecia and gray entostroma D longitudinal sections through pseudostromata E, F immature asci G, H immaure Ascospores I, J conidiophores K-M conidia. Scale bars: 1 mm (A, B); 0.5 mm (C, D); 10 μm (E-M).