Fusarium clavum represents phylo-species FIESC 5 (O’Donnell et al. 2009) resolved as a well-supported clade (ML-BS = 94 %, MP-BS = 82 %, PP = 1.0) in the Equiseti clade, closely related to F. compactum, F. duofalcatisporum, F. ipomoeae and F. lacertarum. All five of these species produce only falcate aerial conidia (Gerlach & Nirenberg 1982, Subrahmanyam 1983, Leslie & Summerbell 2006, Wang et al. 2019), a feature apparently unique to this phylogenetic group. Fusarium clavum forms abundant lateral phialidic pegs on the aerial mycelia, a characteristic shared with F. duofalcatisporum, but not known for F. compactum, F. ipomoeae and F. lacertarum (Gerlach & Nirenberg 1982, Subrahmanyam 1983, Leslie & Summerbell 2006, Wang et al. 2019). However, the falcate aerial conidia of F. clavum (1– 2(– 3)-septate; 13 – 30 × 3 – 4 μm overall) are smaller than those of F. duofalcatisporum (1– 3(– 4)-septate; 13 – 40 × 2 – 5 μm overall). Isolates of F. clavum included in this study were obtained from environmental, plant and human samples collected in Africa, Asia, Europe and North America, indicative of a broad distribution.