Bisifusarium hedylamarriae Y.P. Tan

Zhang, K., Sandoval-Denis, M., Kandemir, H., Yilmaz, N., Groenewald, J. Z., Yáñez-Morales, M. de J., Wingfield, M. J. & Crous, P. W., 2025, Taxonomic revision of Bisifusarium (Nectriaceae), Persoonia 54 (1), pp. 197-223 : 211

Bisifusarium hedylamarriae Y.P. Tan , Index of Australian Fungi 9: 4. 2023. Fig. 7.

New synonym: Fusarium sinense Zhi Yuan Zhang & Y.F. Han, Mycosphere 15: 710. 2024.

Aerial conidiophores scarce, up to 106 µm long, prostate, borne from substrate or submerged mycelium, mostly reduced to solitary, lateral or terminal phialides, or lateral phialidic pegs, rarely laterally branched and multiseptate. Aerial phialides monophialidic, (2.5–)9–22.5(–30) × 1.5– 4 µm, subcylindrical, navicular to subulate, smooth- and thin-walled, with or without a short apical collarette. Aerial microconidia ellipsoidal to somewhat allantoid, often with a minute flattened base, 0-septate, hyaline, smooth and thin-walled, (5.5–)7–10(–12.5) × 2–3.5 µm. Sporodochia light orange to citrine, formed abundantly on the surface and vicinity of carnation leaves. Sporodochial conidiophores up to 50 µm long, smooth- and thin-walled, irregularly and verticillately branched, bearing 1–2 terminal conidiogenous cells. Sporodochial phialides monophialidic, (8.5–)10–16.5(– 21) × 2–3.5 µm, subcylindrical to subulate, smooth- and thin-walled. Sporodochial macroconidia short lunate to falcate, slightly dorsiventrally curved, with a blunt apical end or apical cell and a barely foot-shaped or often not foot-like base or basal cell, 0(–1)-septate, hyaline, smooth- and thin-walled, (8–)9–11(–13) × 2–3.5 µm; Chlamydospores not observed.

Culture characteristics: Colonies in the dark for 7 d at 25 °C: on OA grown in the dark, reaching 4.5–5 cm diam., surface and reverse primrose to straw coloured, flat, margin entire and regular, lacking aerial mycelium. Colonies on PDA reaching 4.5–5.5 cm diam., buff to sulphur yellow, reverse sulphur yellow to straw, flat, with abundant and short aerial mycelium. Margin entire and regular. Colonies on SNA reaching 2–2.4 cm diam., pale buff to straw, flat, irregular with radiate margins.

Typus: Australia, Victoria, Melbourne , on Sansevieria sp. , 7 Oct. 2008, J. Kapitany (holotype BRIP 52699 a, a metabolically inactive culture, culture ex-type BRIP 52699 a = CBS 150895 ) .

Additional materials examined: South Africa, from Aloe dyeri , Nov. 2019, P.W. Crous, culture CBS 153388 = CPC 39039 ; Eastern Cape Province, Amathole, Haga Haga , on leaf of Lederbouria floribunda, Dec. 2014 , M.J. Wingfield, culture CBS 153385 = CPC 25710

Notes: Bisifusarium hedylamarriae was originally described based on unique nucleotide position differences, without a morphological description or illustrations; hence these are provided here ( Fig. 7). This species was found here to encompass strains recently described as B. sinense ( Zhang et al. 2024) , forming a fully supported monophyletic clade, distinct from B. aseptatum and B. australianum . Although tef1 sequences are not identical among all strains of B. hedylamarriae , there is 99.1 % tef1 sequence similarity between both ex-type strains. Additionally, the ex-type strains of B. sinense and B. hedylamarriae show 100 % sequence similarity of ITS and rpb2 sequences. As indicated in the protologue of B. sinense , micro- and macroconidia were difficult to distinguish, hence no separate measurements were included; however, the conidial measurements and morphology shown in the original illustration (microconidia only) match with those of B. hedylamarriae .

Additionally, several morphological features distinguish B. hedylamarriae from its closest phylogenetic relatives B. australianum and B. aseptatum , i.e., yellowish colonies (white in the two latter species), pale orange to citrine sporodochia (greyish orange and yellowish white in B. australianum and B. aseptatum , respectively), and ellipsoidal to allantoid microconidia (ovoid to reniform in B. aseptatum and lacking in B. australianum ).