Dendrostoma dispersum C.M. Tian & N. Jiang

Jiang, Ning, Fan, Xin-Lei, Crous, Pedro W. & Tian, Cheng-Ming, 2019, Species of Dendrostoma (Erythrogloeaceae, Diaporthales) associated with chestnut and oak canker diseases in China, MycoKeys 48, pp. 67-96 : 78-80

Dendrostoma dispersum C.M. Tian & N. Jiang sp. nov. Figure 7

Diagnosis.

Dendrostoma dispersum can be distinguished from the phylogenetically closely related D. mali and D. quercinum based on its conidial dimensions.

Holotype.

CHINA. Shaanxi Province: Beijing City: Mentougou District, Xiaolongmen Forest Park, 39°55'52"N, 115°45'15"E, 1670 m a.s.l., on branches of Quercus sp., 15 Aug. 2017, N. Jiang & X.L. Fan (holotype: BJFC-S1537; ex-type culture: CFCC 52730).

Etymology.

Dispersum, referring to the conidiomata scattered on the bark surface.

Description.

Sexual morph not observed. Asexual morph: Conidiomata pycnidial, conical to spherical, occurring separately, bright yellow, semi-immersed in bark, 500-800 μm high, 900-1500 μm diam.; wall of several layers of bright yellow textura angularis; central column beneath the disc conical, bright yellow. Conidiophores reduced to conidiogenous cells. Conidiogenous cells lining the inner walls of the cavity, hyaline, smooth, subcylindrical to ampulliform, 6-15 × 2.5-5 μm. Conidia hyaline, aseptate, smooth, multiguttulate, thin-walled, ellipsoid to fusoid, straight to curved, (10.9 –)11.1–12.2(– 12.8) × (1.9 –)2–2.3(– 2.4) μm, l/w = (4.8 –)4.9–5.9(– 6.3) (n = 50).

Culture characters.

On PDA, cultures are initially white, becoming faint yellow after 2 weeks. The colonies are flat with regular edge; texture uniform, producing concentric circles within 1 month at 25 °C in the dark.

Additional specimen examined.

CHINA. Beijing City: Yanqing District, Yudu Mountain, 40°53'48"N, 115°54'48"E, 840 m a.s.l., on branches of Quercus sp., 12 Mar. 2018, N. Jiang, X.L. Fan, Y.M. Liang & C.M. Tian, living culture CFCC 52731 (BJFC-S1538).

Notes.

Dendrostoma dispersum is phylogenetically close to D. mali and D. quercinum (Fig. 2). Conidial dimensions of Dendrostoma mali and D. quercinum were described from PDA plates ( Fan et al. 2018) and D. dispersum can be differentiated from D. mali by having much longer conidia (11.1-12.2 μm in D. dispersum vs. 3-4.5 μm in D. mali ) and from D. quercinum by narrower conidia (2-2.3 μm in D. dispersum vs. 2.5-3 μm in D. quercinum ).