Xenoberkleasmium pandani (McKenzie) J. Y. Zhang, Y. Z. Lu & K. D. Hyde, 2025

Zhang, Jing-Yi, Hyde, Kevin D., Yang, Ming-Fei, Sun, Ya-Ru, Xiao, Xing-Juan, Meng, Ze-Bin, Bao, Dan-Feng & Lu, Yong-Zhong, 2025, Discoveries of Dothideomycetes (Fungi) associated with pteridophytes in China, IMA Fungus 16, pp. e 167717-e 167717 : e167717-

Xenoberkleasmium pandani (McKenzie) J. Y. Zhang, Y. Z. Lu & K. D. Hyde comb. nov.

Fig. 6

≡ Berkleasmium pandani McKenzie , Mycotaxon 104: 24 (2008)

Holotype.

MALAYSIA • Genting Highlands, Ganung Buah , in the dead leaves of Pandanus species ( Pandanaceae ), 18 August 1992, E. H. C. McKenzie ( PDD 60532 ) .

Description.

Sexual morph: Undetermined. Asexual morph: Hyphomycetous. Colonies on natural substrate effuse, superficial, scattered to gregarious, sporodochial, velvety, punctiform, brown to black. Mycelium mostly superficial, composed of branched, septate, hyaline to brown hyphae. Conidiophores macronematous, mononematous, cylindrical, hyaline to middle brown, up to 32 µm. Conidiogenous cells monoblastic, holoblastic, terminal, inverted lageniform, clavate, narrowed towards the base, truncate at apex after conidial secession, with dense cytoplasm, hyaline, 13–33 × (4 –) 8.5–12.8 µm ( x ̄ = 23 × 10.5 µm, n = 20). Conidia 25–35 × 15–21 µm ( x ̄ = 30 × 18 µm, n = 30), acrogenous, solitary, oval to ellipsoidal, usually broadly obtuse at apex and slightly truncate at base, thick-walled muriform, not constricted or slightly constricted at the septa, sometimes with a dark median septum, brown.

Culture characteristics.

Conidia germinating on WA within 15 h and germ tube produced from the ends of conidia. Colonies growing on PDA, reaching about. 42 mm diameter in one month at 26 ° C, circular, with an indentation at the entire margin, flat, with a protuberance in the center, dry, celadon to gray from central part to margin from above; pale brown to celadon to brown from center towards the margin from below, and not producing pigmentation in cultures.

Material examined.

CHINA • Guizhou Province, Tongren City, Jiangkou County, ( 27°46'38"N, 108°45'22"E), on dead stems of Woodwardia japonica ( Blechnaceae ) in a forest near the roadside, 21 May 2022, J. Y. Zhang, F 31-1 ( HKAS 147017 = GZAAS 23-0824 ), living culture KUNCC 23-13876 ; • ibid., F 32-1 ( HKAS 129706 = GZAAS 23-0674 ), living culture, KUNCC 23-13878 ; CHINA • Guizhou Province, Qiandongnan Miao and Dong Autonomous Prefecture, Liping County, Yongcong Town , on dead fronds of Blechnopsis orientalis ( Blechnaceae ) in a forest, 27 March 2022, J. Y. Zhang, J 352 ( HKAS 147020 ), living culture KUNCC 23-14012 .

Additional sequence.

KUNCC 23-13876 : ITS ( PV 862369); KUNCC 23-13878 : ITS ( PV 862370); KUNCC 23-14012 : ITS ( PV 862371).

Notes.

Berkleasmium pandani was introduced by McKenzie (2008), but sequence data was not provided. The morphological characters of our new collection align with the original diagnosis of the holotype ( McKenzie 2008), including conidial sizes (25–35 × 15–21 µm vs. 27–34 × 18–22.5 µm). Although there are slight differences in the sizes of conidiogenous cells (13–33 × 8.5–12.8 µm vs. up to 45 µm), this may be attributed to differences in host and environmental conditions. Thus, we identified our new collections as Berkleasmium pandani . The molecular data for this species are generated for the first time. Phylogenetic analysis showed that our three new isolates form a distinct clade within Xenoberkleasmium . The characteristics of these new collections align with the generic concept of Xenoberkleasmium , and therefore, we have transferred them to Xenoberkleasmium .

Notably, Verma et al. (2019) introduced a new geographical record for Berkleasmium pandani based solely on morphological characteristics. However, based on the photographs and descriptions provided by Verma et al. (2019), we found that the elliptical to globose basal cells attached to the conidia were incorrectly described as conidiogenous cells. We therefore consider that the identification of the specimen ( PAN 32722 ) as Berkleasmium pandani requires reevaluation, and we do not accept this specimen provided by Verma et al. (2019) as a valid record of Berkleasmium pandani .

Figures

Figure 6. Xenoberkleasmium pandani (HKAS 147017). A The host; B, C Colonies on the host substrate; D Mycelium; E – K Conidiogenous cells and conidia; L Pure culture from above and below. Scale bars: 20 μm (D – K).