Bisifusarium colchici K. Zhang & Crous 2025, sp. nov.

Bisifusarium colchici K. Zhang & Crous, sp. nov. MB 858740. Fig. 6. Etymology: Name refers to Colchicum, the host genus from which the type strain was isolated. Sporodochia greyish orange, formed abundantly on CLA. Sporodochial conidiophores verticillately branched and densely packed, giving rise to 1–2 conidiogenous cells, subulate to subcylindrical, 2–3 µm wide near aperture, smooth- and thin-walled. Sporodochial macroconidia slender, falcate, slightly curved with almost parallel sides tapering slightly towards both ends, curved apical cell, basal cell curved, generally not foot-like, 2-septate, hyaline, smooth-and thin-walled, (22.0–)23.5(–24.5) × (3.8–)4.0(–4.5) µm. Microconidia aseptate, typically ellipsoidal, straight or curved, allantoid, formed on SNA on submerged or aerial hyphae, average 10 × 2.5 µm; Chlamydospores in PDA and SNA intercalary, solitary or in chains, globose to ellipsoid, smoothwalled, 3–6 µm diam. Culture characteristics: Colonies in the dark for 7 d at 25 °C: on OA grown in the dark, reaching 5.5–6 cm diam., surface and reverse partly light umber. Colonies on PDA reaching 7–8 cm diam., raised in centre. Colonies on SNA reaching 6–6.4 cm diam., flat, radial hyphae extending in the agar, surface and reverse nearly transparent. Typus: South Africa, Western Cape Province, Clanwilliam, leaf spots on Colchicum sp., Sep. 2022, M.J. Wingfield & F. Roets, HPC 4017 (holotype CBS H-25443, culture ex-type CBS 153389 = CPC 45105). Additional materials examined: South Africa, Western Cape Province, Clanwilliam, Trachyandra sp., Sep. 2022, M.J. Wingfield, HPC 4028, culture CBS 153390 = CPC 45109; Western Cape Province, Clanwilliam, Lachenalia sp., Sep. 2022, M.J. Wingfield, HPC 4022, cultures CBS 153391 = CPC 45111, CBS 153392 = CPC 45112. Notes: Bisifusarium colchici is phylogenetically closely related to B. penzigii, from which it differs by 12 bp in the four loci dataset (ITS 1, rpb2 9, and tef1 2, while no tub2 sequences of F. colchici are available for comparison). Morphologically, B. colchici is distinguished by its macroconidial shape (macroconidia equally hooked at both ends in B. colchici vs more strongly apically hooked in B. penzigii), macroconidial size (mostly exceeding 20 µm long in B. colchici vs less than 20 µm long in B. penzigii), and B. colchici has chlamydospores arranged in long chains (Schroers et al. 2009).