Amphisphaeria micheliae Samarak., Jian K. Liu & K. D. Hyde, 2020

Tun, Zaw Lin, Bundhun, Digvijayini, Bhunjun, Chitrabhanu S., Maharachchikumbura, Sajeewa S. N., Thiyagaraja, Vinodhini, Al-Otibi, Fatimah & Hyde, Kevin D., 2025, The addition of six novel species and a new record of Amphisphaeria from northern Thailand, MycoKeys 125, pp. 1-31 : 1-31

Amphisphaeria micheliae Samarak., Jian K. Liu & K. D. Hyde, 2020

Fig. 3

Description.

Saprobic on dead twigs of Senna siamea . Sexual morph: Ascomata 308–320 µm high, 348–360 µm wide, (xˉ = 312 × 353 µm, n = 5), immersed, visible as black spots in light-coloured areas on the host, solitary, scattered, subglobose to oblate, papillate. Ostiole 100–106 µm high, 65–70 µm diam (xˉ = 102 × 67 µm, n = 5), centric. Peridium 45–58 µm (xˉ = 48 µm, n = 5) two-layered; outer layer thick, dense, made up of red-dish-brown cells of textura angularis; inner layer thin, comprising hyaline cells. Paraphyses 3–5 µm wide (xˉ = 4.4 µm, n = 5), hyaline, longer than asci, septate, guttulate, embedded in a gelatinous matrix. Asci 85–115 × 6.5–7 µm (xˉ = 101 × 6.8 µm, n = 20), 8 - spored, unitunicate, cylindrical, thin-walled, short-pedicellate, apically rounded, with a J +, discoid apical ring. Ascospores 15–16 × 5–6 µm (xˉ = 15.5 × 5.9 µm, n = 20), uniseriate, oblong or narrowly fusiform, guttulate, hyaline when immature, turning sub-hyaline to olivaceous grey, 1 - septate, slightly constricted at the septum, straight to slightly curved, smooth-walled, lacking a sheath in Indian ink. Asexual morph: Not observed.

Material examined.

Thailand • Chiang Rai Province, Mae Fah Luang University premises ( 20°02′42″N 99°53′41″E), on dead decaying twigs of Senna siamea ( Fabaceae ), 02 October 2024, Zaw Lin Tun T 7, ( MFLU 25-0077 ) .

Notes.

Based on the phylogenetic analyses, our strain ( MFLU 25-0077 ) clustered with Amphisphaeria micheliae group (Fig. 1 ). Morphologically, our strain ( MFLU 25-0077 ) resembles the type of A. micheliae ( MFLU 20-0172 ) ( Samarakoon et al. 2020). The asci length of our collection ( MFLU 25-0077 ) measures 85–115 × 6.5–7 µm, while those of the type of A. micheliae ( HKAS 107012) range from 92–135 × 7–10.5 µm ( Samarakoon et al. 2020). The ascospore length of A. micheliae ( MFLU 25-0077 and HKAS 107012) is also similar (15–16 × 5–6 µm vs. 15.5–21 × 6–7.5 µm) ( Samarakoon et al. 2020). The comparison of inter-species genetic distances between our strain ( MFLU 25-0077 ) and HKAS 107012 reveals largely similar base pair differences in the LSU (99 %) and ITS (99 %) regions. Based on this morpho-phylogenetic evidence, we identify our isolate as A. micheliae . Previously, A. micheliae was isolated from dead twigs of Acer truncatum , Alstonia scholaris , Micromelum integerrimum , and Michelia alba in China and Thailand ( Samarakoon et al. 2020; De Silva et al. 2022; Li et al. 2024; Pathirana et al. 2025). This is the first report of A. micheliae from Senna siamea in Thailand.

Figures

Figure 1. Phylogram generated from ML analysis based on combined LSU, ITS sequence data. Bootstrap support values for ML ≥ 75 % and PP ≥ 0.90 are indicated near the corresponding nodes. The tree is rooted with Beltrania rhombica (CBS 123.58), Beltraniella endiandrae (CBS: 137976), and Beltraniopsis longiconidiophora (MFLUCC 17-2139). Type and reference strains are in bold, while the novel strains are in bold red.

Figure 3. Amphisphaeria micheliae (MFLU 25-0077). A. Senna siamea tree; B. Appearance of ascomata on host (arrows indicate ascomata visible as black spots); C. Vertical section through an ascoma; D. Vertical section of ascomatal wall; E. Paraphyses; F – H. Asci; I. J + Apical ring; J – L. Ascospores. Scale bars: 200 μm (C); 100 μm (D); 20 μm (E); 5 μm (F, G); 50 μm (H, I); 10 μm (J – L).