The genus Castanediella Author Lin, Chuan-Gen Author J. Bhat, Darbhe Author Liu, Jian-Kui Author D. Hyde, Kevin Author Yong Wang, text MycoKeys 2019 51 1 14 http://dx.doi.org/10.3897/mycokeys.51.32272 journal article http://dx.doi.org/10.3897/mycokeys.51.32272 1314-4049-51-1 Castanediella brevis s C.G. Lin & K.D. Hyde sp. nov. Figure 2 Holotype. THAILAND. Lampang: Amphoe Mueang Pan, Tambon Chae Son, on decaying leaves, 24 September 2016, Chuangen Lin, LCG 10-1 (MFLU 18-1695, holotype; HKAS 102198, isotype), ex-type living cultures KUMCC 18-0132. GenBank number. ITS: MH806361, LSU:MH806358 Etymology. In reference to the short conidiophores. Saprobic on plant host. Asexual morph: Colonies on substrate effuse, white. Mycelium partly superficial, composed of septate, branched, smooth, hyaline to subhyaline hyphae. Conidiophores macronematous, mononematous, solitary, erect, unbranched, straight or flexuous, short, 0-1-septate, hyaline, subcylindrical, ampulliform, smooth, often reduced to conidiogenous cells. Conidiogenous cells holoblastic, polyblastic, sympodial, integrated, terminal, subcylindrical, ampulliform, hyaline, denticulate, with 2-4 tiny protuberant denticles, 3-14 x 1.5-5.5 μm . Conidia solitary, dry, acropleurogenous, smooth, fusiform, curved, aseptate, hyaline, 12.5-21.7 x 1.2-3 μm (av. 16.95 x 2.2 μm , n = 60). Sexual morph: Undetermined. Culture characteristics: Conidia germinating on PDA within 24 h. Colonies on PDA effuse, greyish white to dark from above and below, reaching a diam. of 5-7 cm in 30 days at 25 °C. Notes. Based on a megablast search of the NCBI nucleotide database using the ITS sequence of the ex-type culture, the highest similarities found were with Castanediella malaysiana (GenBank NR_154810; identities = 526/537(98%), gaps = 1/537(0%)) and C. couratarii (GenBank KX960789; identities = 521/538(97%), gaps = 3/538(0%)). Castanediella brevis differs from these two species by its conidiophore morphology. Castanediella couratarii has pale brown conidiophores and longer conidiogenous cells (10.5-37 x 2-3.5 μm ) whereas C. malysiana has pale brown and longer conidiophores (76-157 x 2.5-3 μm ). Among the species that produce more or less falcate and aseptate conidia, Castanediella communis , C. eucalypti , C. eucalypticola and C. eucalyptigena are most similar to C. brevis . However, Castanediella brevis differs from these species by its short, unbranched and 0-1-septate conidiophores. Figure 2. Castanediella brevis (MFLU 18-1695, holotype) a host material b conidiophores on the host surface c-g conidiophores, conidiogenous cells with conidia h conidia. Scale bars: 10 μm ( c-g ), 5 μm (h).