MycoBank 828432

Holotype:— China, Xinjiang Uygur Autonomous Region, Bole Mongol Autonomous Prefecture, 44°46’13.44”N, 81°13’58.72”E, from branches of Picea crassifolia, July 2017, C.M. Tian & X.L. Fan, holotype CF 20176561, ex-type living culture CFCC 52841.

Etymology:—Named after the host genus on which it was collected, Picea.

Descriptions:—Asexual state: Conidiomata pycnidial, ostiolated, immersed in bark, scattered, erumpent through the surface of bark when mature. Locules multiple, discoid, circular to ovoid, arranged vesicularly with common walls, (680–)720–1190(–1200) μm (= 945 ± 130 µm, n = 30) in diam. Conceptacle absent. Ectostromatic disc white to light brown, circular, disc dark, (160–)230–290(–310) µm (= 255 ± 36 µm, n = 30) in diam., with one ostiole in the centre of disc. Ostiole conspicuous, circular to ovoid, dark brown to black at the same level as the disc, (65–)70–115(– 130) µm (= 93 ± 17 µm, n = 30) in diam. Conidiophores hyaline, branched at base or not branched, thin walled, filamentous, (12–)13.5–19.5(–20) μm (= 16.5 ± 3 µm, n = 30). Conidiogenous cells enteroblastic, polyphialidic. Conidia hyaline, allantoid, eguttulate, smooth, aseptate, thin-wall, (4.5–)5–5.5(–6) × 1–1.5 µm (= 5.2 ± 0.3 × 1.3 ± 0.1 µm, n = 50). Sexual morph: not observed.

Culture characteristics: Cultures on PDA are initially white, becoming saffron after one week. The colonies are tight, thin with a uniform texture, lacking aerial mycelium, up to 1.8 cm after four weeks. Sterile.

Materials examined: — China, Xinjiang Uygur Autonomous Region, Bole Mongol Autonomous Prefecture, 44°46’15.32”N, 81°13’57.54”E, from branches of Picea crassifolia, July 2017, C.M. Tian & X.L. Fan, deposited by X.L. Fan, CF 20176562, living culture CFCC 52842.

Notes:— Cytospora piceae is associated with canker disease of Picea crassifolia. The phylogenetic inferences resolved this species as a confused clade in ITS phylogram (Fig. 1), which was closed to Cytospora friesii and C. mougeotii. To clarify this clade, the second analysis indicated this species represented an individual clade with high support value (MP/ML/BI = 100/100/1) based on combined multilocus gene phylogenetic analysis, which was distinguish from other available species (Fig. 2). Morphologically, Cytospora piceae has larger conidia than those of C. friesii (5–5.5 × 1–1.5 vs. 4–5 × 1 µm), and wider than C. mougeotii (5–5.5 × 1–1.5 vs. 5–7 × 0.7–1 μm) (Saccardo 1884). Cytospora piceae is thus here considered as a novel species.