Pestalotiopsis corchorifolii M. G. Liao & Jian Ma 2026, sp. nov.

Pestalotiopsis corchorifolii M. G. Liao & Jian Ma sp. nov. Fig. 3 Type. China • Zhejiang Province, Wenzhou City, Wenzhou Botanical Garden, on diseased leaves of Rubus corchorifolius, 24 October 2023, X. X. Luo (HJAUP M 1891, holotype), ex-type living culture HJAUP C 1891.1 = HJAUP C 1891.2 = HJAUP C 1891.3 = HJAUP C 1891.4 = HJAUP M 1891.5. Etymology. Named after the host species, Rubus corchorifolius, from which the fungus was isolated. Description. Regular leaf spots, grey white in center with brown at margin. Asexual morph on PDA: Conidiomata acervular, globose to clavate, 849–1375 μm diam., solitary or aggregated in clusters, black. Conidiophores indistinct and reduced to conidiogenous cells. Conidiogenous cells hyaline, smooth, cylindrical to ampulliform. Conidia fusiform, straight or slightly curved, 14.6–21.6 × 4.4–5.9 μm (x ̄ = 17.4 × 5.3 μm, n = 50), 4 - septate, slightly constricted at the septa; basal cell conical, 2.2–3.9 μm (x ̄ = 2.6 μm), hyaline, smooth, thin-walled, with a single filiform appendage, unbranched, 0.9–3.1 μm (x ̄ = 2.1 μm) long; three median cells doliiform to cylindrical, smooth, thick-walled, 10.5–14.0 μm (x ̄ = 12.1 μm), concolorous, brown, somewhat constricted at the septa, second cell from the base 3.4–5.6 µm (x ̄ = 4.1 μm) long, third cell 3.3–4.6 µm (x ̄ = 4.1 μm) long, fourth cell 3.4–4.7 µm (x ̄ = 4.0 μm) long); apical cell conical to acute, hyaline, smooth, thin-walled, 1.9–3.7 µm (x ̄ = 2.7 μm) long, with 2–3 filiform appendages, arising from the apex of the apical cell each at a different point, unbranched, 6.7–17.4 µm (x ̄ = 11.5 μm) long. Sexual morph: not observed. Culture characteristics. Colonies on PDA grow fast, filamentous, reaching 85–90 mm diam. after 5–7 days at 25 ° C in light and dark conditions (8 h / 16 h), white, with flocculent mycelium and entire edge, forming black conidiomata, and reverse white. Note. Phylogenetic analyses revealed that the five strains (HJAUP C 1891.1 T, HJAUP C 1891.2, HJAUP C 1891.3, HJAUP C 1891.4, and HJAUP M 1891.5) of P. corchorifolii form a distinct clade sister to P. camelliicola (HJAUP C 1804.221 T and HJAUP C 1804.222) with 98 % ML / 1.00 BI bootstrap support (Fig. 1). Based on a BLASTn search of P. corchorifolii (HJAUP C 1891.1 T) and P. camelliicola (HJAUP C 1804.221 T) in GenBank, comparisons of nucleotides showed 1 bp (630 / 631, including one gap), 5 bp (296 / 301, including three gaps), and 5 bp (476 / 481, including one gap) nucleotide differences in the ITS, tef 1-α, and tub 2 regions, respectively. Moreover, P. corchorifolii can be distinguished from P. camelliicola X. X. Luo & Jian Ma (Luo et al. 2024) by its larger conidiomata (849–1375 μm diam. vs. 470–1320 μm diam.) and smooth, narrower conidia (4.4–5.9 μm vs. 5.7–7.6 μm), and further differs in that the conidia of P. camelliicola have 2–4 tubular apical appendages arising from an apical crest or irregularly branched along their length, resulting in 2–3 branches. Furthermore, P. corchorifolii can be distinguished from P. camelliicola by its different host (Rubus corchorifolius vs. Camellia japonica).