Bisifusarium colchici K. Zhang & Crous, 2025

Bisifusarium colchici K. Zhang & Crous , sp. nov. MB 858740 View Materials . 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 About HPC (holotype CBS H-25443 , culture ex-type CBS 153389 View Materials = CPC 45105 View Materials ) .

Additional materials examined: South Africa, Western Cape Province, Clanwilliam , Trachyandra sp. , Sep. 2022, M.J. Wingfield, HPC 4028 About HPC , culture CBS 153390 View Materials = CPC 45109 View Materials ; Western Cape Province, Clanwilliam , Lachenalia sp. , Sep. 2022, M.J. Wingfield, HPC 4022 About HPC , cultures CBS 153391 View Materials = CPC 45111 View Materials , CBS 153392 View Materials = CPC 45112 View Materials .

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).