Dictyosporium hughesii McKenzie

Dictyosporium hughesii McKenzie, Mycotaxon 111: 156 (2010) Fig. 5 Description. Saprobic on submerged decaying wood. Sexual morph: Undetermined. Asexual morph: Hyphomycetous. Colonies on natural substrate, punctiform, sporodochia, scattered but coalescing, black, irregular. Mycelium immersed, pale to brown. Conidiophores micronematous, mononematous, subhyaline, thin-walled, smooth. Conidiogenous cells holoblastic, determinate, cylindrical, 3.5–5 µm wide. Conidia 56–68 × 23–29 μm (x ̄ = 62 × 26.3 μm, n = 40), solitary, acrogenous, medium brown, complanate, ellipsoidal or cylindrical, cheiroid, arranged in 7 closely adpressed rows of cells, with outer rows of cells arising from a basal cell, the side rows lower than middle rows, outer rows extending about two-thirds of the way along the conidium, each row containing 6–12 cells, constricted at septa, slightly thickened walls and septa, with or without appendages. Cultural characteristics. Conidia germinating on PDA within 24 h and germ tubes produced from the basal cells and the apex of the row of cells. Colonies grew on PDA at 22 ° C, circular, with fluffy mycelium; the mycelium is dense in the center and sparse at the edges, white at the outer margin and light yellow at the center, light yellow on the reverse side. Material examined. China • Yunnan Province, Dulongjiang River, on submerged decaying wood, 2 May 2023 (Altitude: 1418 m, 27.783341°N, 98.330741°E), Ying Wang, S 4812 (KUN-HKAS 135963), living culture, KUNCC 23-15923. Notes. This collection was identified as Dictyosporium hughesii based on the phylogenetic analysis and morphological characteristics. Phylogenetic analysis of the combined ITS, LSU, and tef 1 - α sequence data showed that our new strain (KUNCC 23-15923) clustered with the ex-type strain of Di. hughesii (KT 1847) with 97 % ML and 1.00 PP support (Fig. 1). Morphologically, the conidia of our new collection are slightly larger (56–68 µm vs. 40–47 µm), and the appendages are not prominent. Di. hughesii has been found on dead leaves of Rhopalostylis sapida in New Zealand (McKenzie 2010) and on dead branches of Stewartia monadelpha in Japan (Ghosh et al. 2015; Tanaka et al. 2015), and herein it is reported from submerged decaying wood in a freshwater habitat in China.