Cryphonectria parasitica (Murrill) M.E. Barr, Mycol. Mem. 7: 143. 1978.
Illustration: See Senanayake et al. (2017b).
Pathogenic on branches of Castanea dentata. Sexual morph: Ascostromata 0.5–1 mm diam. (x̅ = 0.8 mm, n = 20), comprising erumpent to superficial, orange epistromatic portion and immersed, hyaline, parenchymatous portion. Ascomata 650–715 µm high, 210–220 µm diam. (x̅ = 685 × 216 µm, n = 20), perithecial, immersed, globose to subglobose, with black to brown ostiole, ostiolar canal slender, covered with orange to fuscous-black stromatic tissue. Hamathecium aparaphysate, comprising parenchymatous tissues. Asci 20–35 × 5–8 µm (x̅ = 28 × 6.4 µm, n = 20), 8-spored, unitunicate, fusiform to cylindrical base with small pedicel, apex oblong. Ascospores 5–6 × 2–2.5 µm(x̅ = 5.5 × 2.2 µm, n = 20), overlapping uni- or biseriate, hyaline, ellipsoid to fusiform, 1-septate. Asexual morph: Conidiomata 250–300 µm high, 180–200 µm diam. (x̅ = 280 × 185 µm, n = 20), eustromatic, erumpent, pyriform to pulvinate, orange to fuscous black, occurring in the same stroma as perithecia. Conidiophores 3–4 × 1–1.5 µm(x̅ = 3.4 × 1.1 µm, n = 20), cylindrical, unbranched, hyaline. Conidiogenous cells 2.5–5 × 0.5–1 µm(x̅ = 3.3 9 0.8 lm, n = 20), phialidic, simple or branched. Conidia 1.8–2.5 × 0.5–1 µm(x̅ = 2.1 × 0.9 µm, n = 20), hyaline, minute, allantoid to cylindrical, aseptate (description based on Senanayake et al. 2017b).
Notes: Cryphonectria is typified by C. parasitica the causal agent of chestnut blight (Anagnostakis 1987; Heiniger and Rigling 1994). This genus consists of 17 species (Index Fungorum 2018). Cryphonectria and Endothia are congeneric (Kobayashi 1970) and Castlebury et al. (2002) suggested that Endothia is suggested being the asexual morph of Cryphonectria. Cryphonectria parasitica, C. cubensis (Bruner) Hodges and C. eucalypti M. Venter & M.J. Wingf. are serious canker pathogens while other species are mostly saprobes (Roane et al. 1986).