Dendrostoma multiguttulum P.C. Ding, Madhushan & Maharachch, 2025

Dendrostoma multiguttulum P.C. Ding, Madhushan & Maharachch , sp. nov. ( FIGURE 2 View FIGURE 2 )

MycoBank: 859477

Etymology – The name reflects the presence of numerous ( multi) small drop-like spots ( gutulum) on the conidia.

Asexual morph: Conidiomata pycnidial, conical, solitary, with a single neck, erumpent through the host bark, locule irregularly-shaped, 110–180 high × 370–410 μm diam (= 150.22 × 397.8 μm, n = 30). Conidiomata wall several layers of light yellow irregular tissues 16–32 μm (= 24.73 μm, n = 30. Conidiophores reduced to conidiogenous cells. Conidiogenous cells lining the inner walls of the cavity, hyaline, smooth, subcylindrical to ampulliform, 9–28.5 × 1–2.5 μm (= 18.2 × 1.68 μm, n = 30). Conidia hyaline, aseptate, smooth, multiguttulate, thin-walled, ellipsoid to fusoid 8.9–10.5 × 1.2–3.9 μm (= 8.36 × 2.71 μm, l/w=3, n = 50). Sexual morph: Not observed.

Colony characteristics: Conidia germinate on PDA at 24 °C within 12 hours, and colonies can reach a diameter of 42 mm after 20 days at the same temperature. Surface is effused, sparse, circular, and white on the surface, transitioning from light brown to black, and white in reverse.

Materials examined: CHINA, Sichuan Province, Mianyang City, Jiangyou County, WuDu Town, 104˚46'16''N, 31˚54′48′′E, 658 m, 20 November 2024, P.C. Ding (HKAS148723, holotype), ex type culture CGMCC3.28975.

Notes: In the multi-gene phylogeny, our collection forms an independent branch close to D. rizhaoense and D. castanopsidis with 100% ML bootstrap support and 1.00 BYPP values. The nucleotide sequences of strain D. multiguttulum show a 99% similarity to D. rizhaoense CFCC 57559 for ITS (468/472 bp, no gaps), a 99% similarity for rpb2 (839/842 bp, no gaps), and a 96% similarity for tef1-α (281/293 bp, with 3 gaps). Additionally, they show a 96% similarity to D. castanopsidis CGMCC 3.25676 for ITS (515/538 bp, with 8 gaps), a 99% similarity for LSU (784/786 bp, no gaps), a 96% similarity for rpb2 (869/904 bp, no gaps), and a 96% similarity for tef1-α (281/293 bp, with 3 gaps). Morphologically, our isolate D. multiguttulum shows significant differences from D. rizhaoense ( Jiang et al. 2024) and D. castanopsidis (Mu et al. 2024) . The conidiogenous cells of D. multiguttulum are more slender (9–28.5 × 1–2.5 μm) than those of D. rizhaoense (8–27.5 × 3–5.5 μm) and are longer than those of D. castanopsidis (5–12.0 × 1–2 μm). The conidia of D. multiguttulum are more regularly shaped, ranging from ellipsoid to fusoid, whereas those of D. rizhaoense are more variable within the same range, and those of D. castanopsidis are cylindrical to clavate. Additionally, D. multiguttulum has longer, more slender conidia (8.9–10.5 × 1.2–3.9 μm) with more numerous small drop-like spots compared to D. rizhaoense (6.4–8.8 × 2.7–3.8 μm) and D. castanopsidis , which has shorter biguttulate conidia (4.0–6.0 × 1.0–2.0 μm). The differences in both molecular phylogeny and morphological characteristics support the distinction of this taxon. Therefore, based on combined phylogenetic and morphological evidence, this specimen is described here as a new species, D multiguttulum .