taxonID	type	description	language	source
637D616DFF9AFFB857CDFF05FEC1FA26.taxon	etymology	Etymology: — The epithet refers to the host genus (Hibiscus) on which the fungus was collected.	en	Weerasinghe, Gayana O., Bhunjun, Chitrabhanu S., Phukhamsakda, Chayanard, Thakshila, Subasingha A. D., Tun, Zaw L., Al-Otibi, Fatimah, Hyde, Kevin D. (2025): Morpho-molecular analyses reveal a novel species Acrocalymma hibisci and a new host record of Acrocalymma medicaginis. Phytotaxa 714 (2): 157-170, DOI: 10.11646/phytotaxa.714.2.4, URL: https://doi.org/10.11646/phytotaxa.714.2.4
637D616DFF9AFFB857CDFF05FEC1FA26.taxon	materials_examined	Holotype: — MFLU 25 - 0067 Saprobic on branches of Hibiscus rosa-sinensis L. Sexual morph: Undetermined. Asexual morph: Coelomycetous. Conidiomata 328 – 352 × 260 – 274 μm (x ̄ = 340 × 265 μm, n = 5), pycnidial, immersed to erumpent, scattered, solitary, globose, ostiolate, dark brown to black. Pycnidia wall 34 – 40 µm (x ̄ = 37 μm, n = 10) wide, of unequal thickness; thick outer layer and thin inner layer, composed of dark brown to hyaline textura angularis cells. Conidiophores reduced to conidiogenous cells. Conidiogenous cells 6 – 8 × 8 – 11 μm (x ̄ = 7.3 × 9.4 μm, n = 20), enteroblastic, phialidic, globose to subglobose, short, simple, aggregated, smooth, determinate, hyaline. Conidia 60 – 72 × 13 – 14 μm (x ̄ = 66 × 14 μm, n = 35), unicellular, cylindrical, obtuse apex and narrow truncate base, straight with 7 transverse septa, thin, smooth walled, continuous to constricted at septa, with a bud scar surrounded by a small sheath like mucilaginous appendage at apex in immature stage. Material examined: — THAILAND. Chiang Rai Province: Mae Fah Luang University, 20 ° 02 ′ 42 ″ N 99 ° 53 ′ 41 ″ E, on a dead branch of Hibiscus rosa-sinensis (Malvaceae), 7 January 2024, Zaw Lin Tun GO 60 (MFLU 25 - 0067, holotype). GenBank Accession Numbers: — ITS: PV 272667, LSU: PV 272668 Notes: — The multi-gene phylogenetic analysis of LSU, SSU and ITS sequences (Fig. 1) shows that our collection (MFLU 25 - 0067) clustered with the strain (MS 30), with 100 % ML and 1 BPP support. BLASTn searches of the ITS sequence of MFLU 25 - 0067 resulted in 100 % identity to fungal endophyte Acrocalymma sp. (MS 30) (Promputtha et al. 2005). However, morphological and ecological data related to MS 30 were not available in Promputtha et al. (2005). Thus, we consider MFLU 25 - 0067 (holotype) and MS 30 as Acrocalymma hibisci. Acrocalymma hibisci formed an independent lineage sister to A. aquaticum (MFLUCC 11 - 0208) with 63 % ML and 0.91 BPP (Fig. 1) bootstrap support. According to the comparison of the pairwise genetic distance between Acrocalymma hibisci (MFLU 25 - 0067) and its sister taxon Acrocalymma aquaticum (MFLUCC 11 - 0208), there was 7.77 % pairwise distance in the ITS region, corresponding to 30 base pair differences out of 386 bp. There was 1.23 % base pair difference in LSU sequences, corresponding to 10 base pair differences out of 815 bp.	en	Weerasinghe, Gayana O., Bhunjun, Chitrabhanu S., Phukhamsakda, Chayanard, Thakshila, Subasingha A. D., Tun, Zaw L., Al-Otibi, Fatimah, Hyde, Kevin D. (2025): Morpho-molecular analyses reveal a novel species Acrocalymma hibisci and a new host record of Acrocalymma medicaginis. Phytotaxa 714 (2): 157-170, DOI: 10.11646/phytotaxa.714.2.4, URL: https://doi.org/10.11646/phytotaxa.714.2.4
637D616DFF9AFFB857CDFF05FEC1FA26.taxon	description	Acrocalymma hibisci differs from A. aquaticum by the size of the conidia, the number of septa and shape of conidiogenous cell (Table 2). Acrocalymma aquaticum was isolated from submerged wood in a freshwater stream in Thailand (Zang et al. 2012, Calabon et al. 2023) while A. hibisci (MFLU 25 - 0067) was isolated from a dead branch of Hibiscus rosa-sinensis in Thailand. Based on phylogeny and morphological evidences A. hibisci is introduced as a new species.	en	Weerasinghe, Gayana O., Bhunjun, Chitrabhanu S., Phukhamsakda, Chayanard, Thakshila, Subasingha A. D., Tun, Zaw L., Al-Otibi, Fatimah, Hyde, Kevin D. (2025): Morpho-molecular analyses reveal a novel species Acrocalymma hibisci and a new host record of Acrocalymma medicaginis. Phytotaxa 714 (2): 157-170, DOI: 10.11646/phytotaxa.714.2.4, URL: https://doi.org/10.11646/phytotaxa.714.2.4
637D616DFF9BFFBA57CDF9C8FC2DFD24.taxon	description	Saprobic on dead stems of Tithonia diversifolia A. Gray. Sexual morph: Ascomata 135 – 180 × 155 – 195 µm (x ̄ = 160 × 175 µm, n = 5), immersed, appearing as black spots, solitary or scattered, subglobose to obpyriform, coriaceous, dark brown, ostiolate with short papillate neck. Peridium 15 – 20 µm wide, consists of 4 – 5 layers; dark brown cells in the thick outer layer, becoming hyaline cells of textura angularis to globosa in the inner layers. Hamathecium 0.5 – 1.5 µm wide, cylindrical to filiform, septate, branching, pseudoparaphyses. Asci 50 – 80 × 8 – 11 µm (x ̄ = 64 × 10 µm, n = 20), 8 - spored, bitunicate, fissitunicate, cylindric-clavate, straight or slightly curved, with a short pedicel and an apically rounded top with ocular chamber. Ascospores 15 – 21 × 3 – 5 µm (x ̄ = 19 × 4 µm, n = 40), overlapping, uni or biseriate, oblong to broadly fusiform with obtuse to slightly obtuse ends, straight or slightly curved, hyaline, smooth, uniseptate, constricted at the septum, with a hyaline gelatinous sheath at the immature stage. Asexual morph: Undetermined.	en	Weerasinghe, Gayana O., Bhunjun, Chitrabhanu S., Phukhamsakda, Chayanard, Thakshila, Subasingha A. D., Tun, Zaw L., Al-Otibi, Fatimah, Hyde, Kevin D. (2025): Morpho-molecular analyses reveal a novel species Acrocalymma hibisci and a new host record of Acrocalymma medicaginis. Phytotaxa 714 (2): 157-170, DOI: 10.11646/phytotaxa.714.2.4, URL: https://doi.org/10.11646/phytotaxa.714.2.4
637D616DFF9BFFBA57CDF9C8FC2DFD24.taxon	materials_examined	Material examined: — THAILAND. Chiang Rai Province: Nang Lae, 20 ° 02 ʹ 42 ʺN 99 ° 53 ʹ 41 ʺE, on a dead branch of Tithonia diversifolia, 6 March 2024, Gayana Oshani GO 68 (MFLU 25 - 0068). Known hosts and distribution: — Root and crown rot of Medicago sativa (Fabaceae) in Australia (Alcorn & Irwin 1987, Trakunyingcharoen et al. 2014), dead stem of Chromolaena odorata (Asteraceae) in Thailand (Mapook et al. 2020), dead stem of Tithonia diversifolia (Asteraceae) in Thailand (this study). Notes: — Multigene phylogenetic analyses (Fig. 1) showed that our species, Acrocalymma medicaginis (MFLU 25 - 0068), clustered with A. medicaginis (MFLUCC 17 - 1423, MFLUCC 17 - 1439) isolates with 78 % ML and 1.00 BPP. According to the BLASTn of ITS sequence data showed similarities to A. medicaginis (MFLUCC 17 - 1423) of 98.85 % similarity across 97 % of the query sequence. BLASTn searches of the SSU and LSU sequence data showed that our species is 99.76 % and 99.73 % identical to A. medicaginis (MFLUCC 17 - 1423), respectively. Morphologically, Acrocalymma medicaginis is similar to our collection by having subglobose to obpyriform ascomata, hyaline, cylindric-clavate asci, and oblong to broadly fusiform ascospores surrounded by a hyaline gelatinous sheath (Mapook et al. 2020). The first sexual morph of Acrocalymma medicaginis was reported on Chromolaena odorata from Thailand (Mapook et al. 2020), whereas our new isolate was reported on fallen dead branches of Tithonia diversifolia from Thailand. Based on molecular and morphological data, we identify our isolate as A. medicaginis, and this is the first report of A. medicaginis on Tithonia diversifolia from Thailand.	en	Weerasinghe, Gayana O., Bhunjun, Chitrabhanu S., Phukhamsakda, Chayanard, Thakshila, Subasingha A. D., Tun, Zaw L., Al-Otibi, Fatimah, Hyde, Kevin D. (2025): Morpho-molecular analyses reveal a novel species Acrocalymma hibisci and a new host record of Acrocalymma medicaginis. Phytotaxa 714 (2): 157-170, DOI: 10.11646/phytotaxa.714.2.4, URL: https://doi.org/10.11646/phytotaxa.714.2.4
