Cytospora ampla Ning Jiang

Pei, Tingqian, Xiong, Dianguang & Liang, Yingmei, 2025, New species and records of Cytospora (Cytosporaceae, Diaporthales) from tree branches in Hebei Province, China, MycoKeys 126, pp. 187-212 : 187-212

Cytospora ampla Ning Jiang , Persoonia 55: 389 (2025)

Fig. 4

Description.

Sexual morph: Stromata Group SIII (type s 8), immersed in the bark, erumpent through the surface when mature, without extending to a large circular area. Conceptacle absent. Disc light grey, surrounded by ostiolar, circular to ovoid, 64–206 µm in diam, with 12–18 ostioles irregularly circularly in the disc. Ostioles umber to black when mature, arranged regularly in a disc, flask-shaped to spherical, 73–201 µm in diam. Asci hyaline, with a chitinoid, refractive ring, clavate to elongate-obovoid, 60–77 × 11–13 (av. = 46.4 ± 1.9 × 9.4 ± 0.7, n = 30) µm, 4 - spored. Ascospores hyaline, elongate-allantoid, thin-walled, aseptate, 18.8–24.0 × 4.5–6.2 (av. = 20.2 ± 0.4 × 5.3 ± 0.8, n = 50) µm. Asexual morph: not observed.

Culture characteristics.

Colonies initially white and entirely covering the 6 cm Petri dish after 5 d, becoming olivaceous buff to slight helical after 14 d. The colonies are flat, felt-like, thin with a uniform texture.

Materials examined.

China, Hebei Province, Saihanba , 42°23'33"N, 117°22'17"E, from branches of Malus spectabilis , 11 September 2024, C. M. Tian, T. Q. Pei & M. H. Wang ( BJFC -S 2549 , living cultures CFCC 72603 ; BJFC -S 2550 , living culture CFCC 72604 ) ; 42°23'33"N, 117°22'17"E, from branches of Salix matsudana , 8 July 2024, C. M. Tian, T. Q. Pei & Y. Y. Wu ( BJFC -S 2551 , living culture CFCC 72627 ) .

Notes.

Cytospora ampla was initially isolated from branches of Salix sp. and Rubus biflorus in Xizang, China. This species is characterized by its sexual morphs having four-spored asci ( Jiang et al. 2025 a). In the present study, we obtained three new isolates ( CFCC 72603 , CFCC 72604 , and CFCC 72627 ) from Malus spectabilis and Salix matsudana . These isolates clustered robustly with the ex-type isolate CFCC 71044 (Fig. 3 ) with high support ( MLBP / BPP = 92 / 1.00), confirming their identification as C. ampla . Therefore, this represents a new host record ( M. spectabilis ) for C. ampla and its first occurrence in Hebei Province, China.

Figures

Figure 3. Phylogenetic tree inferred from ML analysis based on combined ITS, act, rpb 2, tef 1 - α, and tub 2 sequence data of the Ribis SC. The tree was rooted with Cytospora donglingensis (CFCC 53159) and C. viticola (CBS 141605). Numbers above the branches indicate MLBP ≥ 75 % and BPP ≥ 0.90. Ex-type isolates are in bold. Isolates in this study are highlighted in two different colors, with the new species shown in orange and the known species shown in green.

Figure 4. Cytospora ampla (BJFC - S 2549). A, B. Habit of pseudostromata on branch; C. transverse section through pseudostroma with ascomata; D. Longitudinal section through pseudostroma with ascomata; E, F. Asci; G. Ascospores. Scale bars: 100 μm (B – D); 10 μm (E – G).