Apiospora bambusiparasitica X. Y. Chang & M. J. Chen 2025, sp. nov.

Apiospora bambusiparasitica X. Y. Chang & M. J. Chen sp. nov. Fig. 3 Etymology. The name refers to the species that is capable of infecting the culm of bamboo. Typification. China • Hunan Province, Xiangxi Tujia and Miao Autonomous Prefecture, Ningyuan County, Jiuyi Mountain (25°24'N, 111°58'E), on diseased culms of bamboo, November 2022; X. H. Yue, holotype H 5, ex-type RCEF 20003. Description. Asexual morph: Hyphae 1.5–5.0 µm diam, hyaline, branched, septate. Conidiogenous cells hyaline to pale brown, smooth, erect or flexuous, scattered or aggregated in clusters on hyphae, ampulliform to clavate, 7.0–17.0 × 2.0–4.5 µm (x ̄ = 9.6 ± 2.6 × 2.7 ± 0.7, n = 40), apical neck 6.0–10.0 µm long, basal part 3.0–6.0 µm long. Conidia 7.0–11.5 × 6.0–10.5 µm (x ̄ = 9.2 ± 0.9 × 8.1 ± 1.1, n = 40), brown, smooth to finely roughened, granular, globose to ellipsoid in surface view, usually with a longitudinal, hyaline, germ-slit. Sexual morph: Undetermined. Culture characteristics. Colonies on PDA fluffy, spreading, margin irregular, with abundant aerial mycelia, surface and reverse white to grey, reaching 9 cm in 8 d at 25 ° C. On MEA, the colony is thick in the middle and thin at the edges. The margin is irregular, the surface white, and the central color on the colony’s reverse side is characterized by a deeper, brownish-yellow tone that extends towards the periphery and transitions to a lighter, pale yellow shade. Additional specimens examined. China • Hunan Province, Ningyuan County, diseased on culms of bamboo, November 2022, other living culture RCEF 20000. Note. Phylogenetic analyses confirmed that A. bambusiparasitica formed an independent clade (1.0 BIPP and 100 % MLBS), exhibiting a close evolutionary relationship with A. arctoscopi and A. obovata. Based on a BLASTN search of the GenBank database, it was found that A. bambusiparasitica shares high similarities with the following strains: A. arctoscopi strain KUC 21331 (86.48 % in ITS, 98.9 % in LSU, 92.2 % in TEF 1, 92.91 % in TUB 2); A. obovata strain LC 4940 (90.03 % in ITS, 95.77 % in LSU, 93.42 % in TEF 1, 95.27 % in TUB 2); strain LC 8177 (90.15 % in ITS, 95.77 % in LSU, 93.42 % in TEF 1, 95.27 % in TUB 2). Morphologically, A. bambusiparasitica and A. obovata show distinct differences. Apiospora obovata forms darker colonies and produces significantly longer, ellipsoidal conidia, measuring 16.0–31.0 × 9.0–16.0 µm, whereas A. bambusiparasitica has spherical to oval conidia, measuring 8.6–15.4 × 6.7–10.2 µm. Apiospora bambusiparasitica and A. arctoscopi are morphologically similar, with conidia of comparable size and overlapping dimensions. However, A. arctoscopi forms thicker colonies with more developed hyphae. Additionally, the two species exhibit significant ecological differences in host association, as A. arctoscopi is associated with Arctoscopus japonicus, while A. bambusiparasitica is associated with bamboo. Current fungal taxonomy emphasizes the importance of host association. For details, see Table 2. Thus, both morphological and molecular evidence support A. bambusiparasitica as a new species.