Taxonomic circumscription of melanconis-like fungi causing canker disease in China Author Fan, Xinlei Author Du, Zhuo Author Bezerra, Jadson D. P. Author Tian, Chengming text MycoKeys 2018 42 89 124 http://dx.doi.org/10.3897/mycokeys.42.29634 journal article http://dx.doi.org/10.3897/mycokeys.42.29634 1314-4049--89 Sheathospora cornuta (C.M. Tian & Z. Du) Fan comb. nov. Fig. 9 Basionym. Melanconiella cornuta C.M. Tian & Z. Du, Phytotaxa 327(3): 257 (2017) Diagnosis. This species is distinguished by conical and discrete pycnidia without central column and aseptate, cylindrical to ellipsoidal, (19 -)19.5-22.5(- 23) x (8 -)8.5-10.5(- 11) μm conidia, with a distinct hyaline sheath 1-1.5 μm wide. Holotype. CHINA. Shaanxi Province: Ankang City, Ningshan County, Huoditang Forest Farm, 33°26'04.46"N , 108°26'59.91"E , 3 July 2016, on twigs and branches of Cornus controversa , X.L. Fan (BJFC-S1375 holotype; living ex-type culture CFCC 51990). Descriptions. Conidiomata pycnidial, immersed in host bark, conical, with single necks erumpent through the surface of host branches, scattered, (250 -)270-330(- 410) μm (av. = 300 μm , n = 20) diam. Ectostromatic disc inconspicuous and extended to form a beak at maturity, pale luteous to amber. Central column absent. Conidiophores hyaline, smooth, cylindrical, simple, rarely branched at the base, 17 -24(- 25) x 2.5 -4(- 4.5) μm (av. = 21.5 x 3.5 µm , n = 50). Conidiogenous cells hyaline, phialidic. Conidia hyaline, aseptate, cylindrical to ellipsoidal, (19 -)19.5-22.5(- 23) x (8 -)8.5-10.5(- 11) μm (av. = 21 x 10 µm , n = 50), with distinct hyaline sheath, 1-1.5 μm wide at maturity. Sexual morph was not observed. Figure 9. Morphology of Sheathospora cornuta from Cornus controversa . A-B Habit of pycnidia on branches C-D transverse section through pycnidium E longitudinal section through pycnidium F conidiophores, conidiogenous cells G conidia. Scale bars: 5 mm (A), 1 mm (B), 500 μm ( C-E ), 20 μm ( F-G ). Culture characteristics. Colony growth on PDA originally white, becoming pale yellowish after 7-10 days. Colony flat, felty-like, with a uniform texture and yellowish to dark brown conidiomata irregularly scattered on the colony surface. Additional specimens examined (paratypes). CHINA. Shaanxi Province: Ankang City, Ningshan County, Huoditang Forest Farm, 36°26'13.30"N , 108°26'48.32"E , 3 August 2015, on twigs and branches of Juglans regia , Q. Yang (BJFC-S1345 paratype; living ex-paratype culture CFCC 51991). Notes . Sheathospora cornuta is proposed here as a new combination for Melanconiella cornuta . It is the type and currently only species of Sheathospora and so far known from Cornus controversa and Juglans regia in China. The sexual morph of this species is unknown and further collections are required to elucidate its life cycle.