Cytospora schulzeri Sacc. & P. Syd., Syll. fung. (Abellini) 14(2): 918. 1899. Figure 7

Description.

Sexual morph: not observed. Asexual morph: Pycnidial stromata ostiolated, immersed in bark, scattered, erumpent through the surface of bark, flat, discoid, with multiple locules. Conceptacle absent. Ectostromatic disc brown, circular to ovoid, (250-)300-400(-475) µm diam., with 1-5 ostiole per disc. Ostioles black, at the same level as the disc, (40-)50-85(-115) μm diam. Locule numerous, arranged circularly with common walls, (600-)700-1500(-1750) µm diam. Peridium comprising a few layers of cells of textura angularis, with innermost layer brown, outer layer brown to dark brown. Conidiophores hyaline, unbranched, thin walled, filamentous. Conidiogenous cells enteroblastic polyphialidic, (6.5-)8.5-18.5(-21) × 1-2 μm (x̄ = 13.1 × 1.6 μm). Conidia hyaline, allantoid, smooth, aseptate, thin-walled, (3.5-)4.5-6.5(-7) × 1-1.5 μm (x̄ = 5.2 × 1.3 μm).

Specimens examined.

China, Hebei Province, Chengde City, Kuancheng County, chestnut plantation, 40°38'37"N, 118°27'54"E, on branches of Castanea mollissima, 13 October 2017, N. Jiang (living culture CFCC 52468; BJFC-S1702, living culture CFCC 52469; BJFC-S1703, living culture CFCC 52470).

Notes.

Cytospora schulzeri is a common species causing apple canker disease in China (Teng 1963, Tai 1979, Wei 1979, Zhuang 2005, Fan et al. 2020). In this study, fresh specimens were collected from diseased branches of chestnut trees and identified as Cytospora schulzeri, based on the strictly matched asexual morph (4.5-6.5 × 1-2 μm from Castanea mollissima in this study vs. 4-7 × 1-1.5 μm from multiple specimens in Fan et al. (2020)) and phylogenic analysis (Fig. 2).