Hermatomyces pyriformis H.Z. Du & Jian K. Liu, sp. nov. Fig. 2

MycoBank number: MB 853034

Etymology: — pyriformis refers to pyriform-like shape of the conidiogenous cells.

Holotype: — HKAS 132457

Saprobic on dead branches of Eleutherococcus nodiflorus (Araliaceae). Sexual morph: Undetermined. Asexual morph: Colonies on natural substrate sporodochial, superficial, scattered, circular or oval, black, shiny. Mycelium partly immersed, partly superficial, composed of subhyaline to brown, septate, branched hyphae, 1–3 µm wide. Conidiophores micronematous, indistinct, hyaline, short, smooth-walled. Conidiogenous cells monoblastic, integrated, terminal, determinate, hyaline, pyriform, smooth, or sometimes finely verruculose, 6–14 µm (x̅ = 8 µm, n = 20) long, 5–12 µm (x̅ = 8 μm, n = 20) wide at the widest part. Conidia of one type, solitary, acrogenous, lenticular, globose to subglobose or ellipsoidal in front view, muriform, constricted at septa, smooth, central cells dark brown to blackish brown, peripheral cells with 6–10 cells, brown to dark brown, rarely pale brown, ellipsoidal or oblong in side view, consisting of two adpressed halves, each half with a deep constriction, end cells light brown to brown, central cells brown to dark brown, 10–19 μm (x̅ = 14 µm, n = 30) long, 9–15 μm (x̅ = 12 µm, n = 30) wide and 8–12 μm (x̅ = 10 μm, n = 30) thick.

Culture characteristics: — Conidia germinated on PDA within 24 h, and germ tubes produced from peripheral cells. Colonies growing on PDA reached 18–20 mm diam after three weeks at 25 ℃, circular, dense, margin entire, surface unsmooth with some dark brown lipid droplets, off-white in the center, light green in the middle ring, and greyish-white at the margin from above; greyish-green in the center, presented a greenish ring around, white to pale greyish at the edge from reverse.

Material examined: — CHINA, Yunnan Province: Xishuangbanna Dai Autonomous Prefecture, Mengla County, Xishuangbanna tropical botanical garden Chinese Academy of Sciences. 101°15′3′′E, 21°55′38′′N, elevation 518 m, on dead branches of medicinal plant Eleutherococcus nodiflorus (Dunn) S.Y. Hu (Araliaceae), 10 November 2022, H. Z. Du, S 640 (HKAS 132457, holotype; HUEST 23.0442, isotype); ex-holotype living culture CGMCC 3.27462; ex-isotype living culture UESTCC 23.0441.

Notes: —Phylogenetic analyses (Fig. 1) showed that our two isolates (CGMCC 3.27462 and UESTCC 23.0441) formed a distinct lineage basal to other Hermatomyces strains. Morphologically, Hermatomyces pyriformis is similar to other species in having sporodochial conidiomata and brown, muriform lenticular conidia (Hashimoto et al. 2017, Hyde et al. 2019, Ren et al. 2021, Wijayawardene et al. 2021, Zhang et al. 2023). However, H. pyriformis has unique hyaline, pyriform conidiogenous cells, which are absent in other Hermatomyces species (Koukol et al. 2018, Ren et al. 2021, Zhang et al. 2023). In addition, H. pyriformis can be distinguished from H. dimorphus, H. uniseriatus and H. truncates (three species that lack molecular data) by having pyriform conidiogenous cells and smaller lenticular conidia (Table 3) while these three species have dimorphic conidia (lenticular and cylindrical). Therefore, the new species H. pyriformis is introduced based on morphology and phylogeny.