Dermea chinensis C.M. Tian & N. Jiang

Jiang, Ning & Tian, Cheng-Ming, 2019, Re-collection of Dermeaprunus in China, with a description of D. chinensis sp. nov., MycoKeys 50, pp. 79-91 : 79

Dermea chinensis C.M. Tian & N. Jiang sp. nov. Figures 2, 3

Diagnosis.

Dermea chinensis differs from D. molliuscula by its wider ascospores

Holotype.

CHINA. SHAANXI PROVINCE, Ankang City, Huoditang forest park, 33°26'12"N, 108°26'42"E, 1650 m a.s.l., on branches of Betula albosinensis , N. Jiang & C.M. Tian leg., 18 Jul 2018 (holotype BJFC-S1729). Ex-type culture from sexual fruiting body: CFCC 53008; living culture from asexual fruiting body: CFCC 53009.

Etymology.

Named after the country where it was first discovered, China.

Description.

Sexual Asexual morph: apothecia erumpent, scattered or sometimes gregarious, circular, sinuate, sessile to substipitate, 2.1-3.5 mm wide, 0.8-1.2 mm high (av. = 2.7 × 0.9 mm, n = 10), dark brown to black, hard, leathery to horny in consistency, hymenium at the first concave, becoming plane or convex, roughened, sometimes cracked, occasionally slightly umbilicate; tissue of the basal stroma pseudoparenchymatous, composed of closely interwoven hyphae with elongated cells about 8 μm in diameter, hyaline to brownish, thick walled, curving towards the outside, forming a darker, pseudoparenchymatous excipulum of thick-walled cells about 8 μm in diameter; subhymenium a narrow zone of closely interwoven hyphae about 3 μm in diameter. Asci 85-118 × 14-19 μm (av. x‒= 96.5 × 16.4 μm, n = 10), cylindric-clavate, tapering below into a short stalk, 8-spored. Paraphyses hyaline, filiform, septate, simple or branched, 1.5-2.5 in diameter, the tips slightly swollen up to 4 μm and glued together forming a yellowish epithecium. Ascospores (14.2 –)16.3–17.1(– 18.6) × (7.3 –)7.5–8.5(– 8.9) μm, l/w = (1.8 –)1.9–2.2(– 2.3) (n = 50), ellipsoid-fusiform, hyaline to yellowish-brown, straight or slightly curved, aseptate, irregular biseriate. Asexual morph: conidial fruiting bodies erumpent, gregarious, columnar to subconical, 0.5-2.5 mm wide, 0.4-0.7 mm high (av. = 1.6 × 0.6 mm, n = 10), yellowish, furfuraceous to glabrous, tearing open irregularly and widely at the top, waxy in consistency, more fresh when moist, usually containing 3-8 more or less lobed cavity. Conidiophores 7-18 × 2-3.5 μm, hyaline, aseptate, unbranched, tapering to a slender tip. Conidiogenous cells 5-15 × 1.5-3 μm, determinate, phialidic, cylindrical, hyaline. Conidia (54 –)60–72(– 78) × (3.2 –)3.5–4(– 4.2) μm, hyaline, fifiform, straight or curved, one-celled. Microconidia absent.

Culture characters.

On MEA at 25 °C colonies grow slowly, reaching 50 mm diameter within 60 d, pale yellow at first, gradually turning dark brown with scanty aerial mycelium.

Habitat and host range.

On dead corticated branches of Betula albosinensis .

Additional specimen examined.

CHINA. SHAANXI PROVINCE, Ankang City, Qinling Mountain, 33°26'12"N, 108°26'42"E, 1570 m a.s.l., on branches of Betula albosinensis , N. Jiang & C.M. Tian leg., 15 Jul 2018 (BJFC-S1730, living culture CFCC 53010).

Notes.

Three isolates of D. chinensis were obtained from Betula albosinensis cluster in a well-supported clade (MP/ML = 100/100) and appeared closely related to D. cerasi from Prunus branches. Dermea chinensis and D. cerasi are similar in macroconidia dimensions (54-78 × 3.2-4.2 μm in D. chinensis vs 40-60 × 2.5-4.5 μm in D. cerasi ) but different in ascospore dimensions (14.2-18.6 × 7.3-8.9 μm in D. chinensis vs 15-20 × 5-7.5 μm in D. cerasi ) and host associations ( Groves 1946). Furthermore, the two species are separated by 51 bp differences in their ITS. Dermea molliuscula , which occurs in the USA and Canada, is the other species inhabiting Betula trees. However, D. chinensis is distinguished from D. molliuscula by aseptate ascospores and in width (7.3-8.9 μm in D. chinensis vs 4-7 μm in D. molliuscula ) ( Groves 1946).