Stachylidium chayuense C. Ma, S.C. He & Q. Zhao, 2025

Ma, Chao, He, Shu-Cheng, Cai, Tong, Li, Cui-Jin-Yi, Yu, Feng-Ming, Wang, Zhi-Yang, Zhang, Ying & Zhao, Qi, 2025, A new species of Stachylidium (Trichosphaeriaceae) from Xizang, China, Phytotaxa 694 (1), pp. 77-85 : 80-82

Stachylidium chayuense C. Ma, S.C. He & Q. Zhao , sp. nov. ( FIGURE 2 ) Index Fungorum number: IF902678

Etymology: The specific epithet refers to the locality from where the species was collected.

Saprobic on dead twig. Sexual morph: Undetermined. Asexual morph: Hyphomycetous. Colonies on the substrate, black, white at middle and apex, irregular, dry. Conidiophores simple, straight or flexuous, unbranched, thick and rough-walled, septate, the lower part brown, smooth, and pale olive to hyaline from the middle to apex, verruculose, verticillate, bearing up to 13 whorls with 3–4 conidiogenous cells for each whorl, 300–440 × 4–6 μm (x̄ = 376 × 5 μm, n = 10). Conidiogenous cells 10–14 × 4–6 μm (x̄ = 12 × 5 μm, n = 17), cylindrical to ellipsoidal, verruculose, thick, rough-walled, hyaline to pale brown. Conidia 5–10 × 2.1–5 μm (x̄ = 7 × 3 μm, n = 30), oblong with obtuse ends, solitary, pleuroacrogenous, smooth, thick-walled, aseptate, guttulate, hyaline.

Culture characteristics: Germinating within 12 hours on PDA at 25 °C, reaching 0.8–1.1 cm after 20 days, colony black on the above, with white hairy mycelium, irregular, filamentous, convex, rough on the surface, mycelia dense, reverse grey with white edge, irregular, no pigment.

Material examined: CHINA, Xizang, Linzhi, Chayu , alt. 1,786 m (28°55′N, 96°98′E), on dead twig, 13 Aug. 2023, coll. Shu-Cheng He, WZY11 ( HKAS 134942 , holotype), ex-type living culture, KUNCC 24-17792 ; ibid., coll. Shu-Cheng He, MC23 ( HKAS 134941 ) ; living culture, KUNCC 24-17923 .

Notes: In our phylogenetic analysis, Stachylidium chayuense is positioned within the Stachylidium lineage and is a sister species to S. pallidum ( Fig. 1 ). Regarding morphological characteristics, unlike S. bicolor ( Giraldo & Crous 2019) and S. pallidum ( Dewi 2006) , S. chayuense displays simple, unbranched conidiophores with a greater number of whorls of conidiogenous cells (up to 13 whorls). In the phylogenetic tree ( Fig. 1 ), S. bicolor and S. pallidum are represented as two distinct clades, which further corroborates the classification of these two species as separate species.

Figures

FIGURE 1. Phylogram generated from maximum likelihood analysis based on concatenated LSU, ITS, tef-1α and rpb2 sequence data. The scale bar indicates 0.03 changes per site. Bootstrap support values for ML analysis equal to or greater than 70% and posterior probability for BI analysis equal to or higher than 0.90 are shown on the nodes. The type strains are in bold and the newly generated sequences are indicated in red.

FIGURE 2. Stachylidium chayuense (HKAS 134942, holotype) a Host substrate. b Colonies on natural substrate. c–e Conidiophores (e verruculose on the surface of Conidiophores). f Base of Conidiophores. g Conidiogenous cells. h–w Conidia. x Culture on PDA. Scale bars: c–e = 50 μm. f–g = 20 μm. h–w = 5 μm.