Phialoseptomonium eucalypti Crous & Carnegie, sp. nov.

MycoBank number: MB 830830; Index Fungorum number: IF 830830; Facesoffungi number: FoF

Etymology. Name refers to Eucalyptus, the host genus from which this fungus was isolated.

Mycelium consisting of hyaline, smooth, branched, septate, 1.5 – 2 mm diam hyphae. Conidiophores erect, straight to flexuous, arising directly from hyphae or from a basal stalk, subcylindrical, 0 – 2-septate, 10 – 30 × 3 – 4.5 mm, giving rise to a rosette (2 – 6) of conidiophores. Conidiophores erect, flexuous, subcylindrical with apical taper, hyaline but base at times appearing greenish olivaceous, 5 –7-septate, 190 – 220 × 2.5 – 3 mm. Conidiogenous cells apical, integrated, subcylindrical, phialidic with minute non-flared collarette (1 mm long), apex 1.5 – 2 mm diam, 90 –120 × 2.5 – 3 mm. Conidia solitary, aggregating in mucoid mass, hyaline, smooth, granular, fusoid, straight, medianly 1-septate, apex obtuse, base truncate, 1.5 mm diam, (16 –)19 – 21(– 23) × 3(– 3.5) mm.

Culture characteristics — Colonies flat, spreading, with folded surface, moderate aerial mycelium and smooth, lobate margin, reaching 60 mm diam after 2 wk at 25 °C. On MEA surface and reverse luteous. On PDA surface and reverse pale luteous. On OA surface saffron.

Typus. AUSTRALIA, New South Wales, Boorabee State Forest, McCorquo- dale plantation, on leaves of Eucalyptus grandis × camaldulensis clone (Myrtaceae), 20 Apr. 2016, A.J. Carnegie, HPC 2431 (holotype CBS H-23941, culture ex-type CPC 35732 = CBS 145542, ITS and LSU sequences Gen- Bank MK876402.1 and MK876443.1).

Notes — Phialoseptomonium eucalypti clusters with two acremonium-like isolates (Giraldo & Crous 2019), namely ‘A. lichenicola’ CBS 303.70 and ‘A. rhabdosporum’ CBS 438.66, which may be congeneric. Both the latter species have cylindrical, septate conidia.

Based on a megablast search of NCBIs GenBank nucleotide database, the closest hits using the ITS sequence had highest similarity to Acremonium lichenicola (GenBank MH859549.1; Identities = 542/596 (91 %), 14 gaps (2 %)), Acremonium rhab­ dosporum (GenBank MH858850.1; Identities = 535/593 (90 %), 10 gaps (1 %)) and Trichonectria rectipila (GenBank NR_160175.1; Identities = 465/523 (89 %), 13 gaps (2 %)). The ITS sequence is also 2 – 6 nucleotides similar to unidentified sequences from an unpublished study on dark pigmented epifoliar fungi forming sooty patches on trees in a tropical rainwood forest (GenBank HE584928.1–HE584933.1). Closest hits using the LSU sequence are Acremonium lichenicola (GenBank MH871536.1; Identities = 798/816 (98 %), no gaps), Sarcopodium flavolana­ tum (GenBank MH876362.1; Identities = 794/816 (97 %), no gaps) and Sarcopodium macalpinei (GenBank MH876364.1; Identities = 791/816 (97 %), no gaps).

Species