Neocalonectria tristaniopsidis Crous, sp. nov.

MycoBank number: MB 837820; Index Fungorum number: IF 837820; Facesoffungi number: FoF14516;

Etymology. Name refers to the host genus Tristaniopsis from which it was isolated.

Conidiophores consisting of a stipe, a penicillate arrangement of fertile branches, one to several avesiculate stipe extensions, lacking a terminal vesicle; stipe septate, hyaline, smooth, 30 –70 × 5 – 6 µm; stipe extensions septate, straight to flexuous, 70 –150(– 200) µm long, 3 – 4 µm wide at the apical septum, terminating in an acicular apical cell. Conidiogenous apparatus 50 – 80 µm long, 30 – 50 µm wide; primary branches aseptate or 1-septate, 12 – 20 × 4 – 5 µm; secondary branches aseptate, 10 –12 × 3 – 4 µm, and tertiary branches aseptate, 8 –10 × 3–4 µm, each terminal branch producing 2 – 6 phialides; phialides elongate doliiform to reniform, hyaline, aseptate, 8 –12 × 2.5 – 4 µm, apex with minute periclinal thickening and inconspicuous collarette. Conidia cylindrical, rounded at both ends, straight to gently curved, (39 –)40 – 43(– 46) × 3 (– 3.5) µm (mean 42 × 3 µm), 1-septate, lacking a visible abscission scar, held in parallel cylindrical mucoid clusters. Mega– and microconidia not seen.

Culture characteristics — Colonies erumpent, spreading, with moderate aerial mycelium and smooth, even margin, cov- ering dish after 2 wk at 25 °C. On MEA, PDA and OA surface ochreous, with chains of brown, thick-walled chlamydospores.

Typus. AUSTRALIA, New South Wales, Limpinwood Nature Reserve, on leaves of Tristaniopsis collina (Myrtaceae), 26 May 2015, B.A. Summerell, HPC 2948 (holotype CBS H-24396, culture ex-type CPC 38081 = CBS 146800, ITS, LSU, actA, cmdA, his3, rpb2, tef1 and tub2 sequences GenBank MW175333.1, MW175373.1, MW173091.1, MW173097.1, MW173106.1, MW173109.1, MW173118.1 and MW173130.1).

Additional material examined. AUSTRALIA, New South Wales, Limpinwood Nature Reserve, on leaves of T. collina, 26 May 2015, B.A. Summerell, HPC 2948, CBS H-24400, culture CPC 38155 = CBS 146805, ITS, LSU, actA, cmdA, his3, rpb2, tef1 and tub2 sequences GenBank MW175334.1, MW175374.1, MW173092.1, MW173098.1, MW173107.1, MW173110.1, MW173119.1 and MW173131.1.

Notes — Neocalonectria resembles Calonectria and Xenocylindrocladium in having penicillate conidiophores with hyaline, cylindrical, septate conidia (Crous 2002). Morphologically it is closer to Xenocylindrocladium, as it has multiple stipe extensions per conidiophore that lack terminal vesicles (Decock et al. 1997, Crous et al. 2001). Neocalonectria forms a well-supported clade closely related to the genera Calonectria, Curvicladiella and Xenocylindrocladium (Lombard et al. 2015). Although several stipe extensions were observed arising from conidiophores on host material, cultures of Neocalonectria sporulate profusely, but rarely form stipe extensions on synthetic nutrient- poor agar. Morphologically it is hard to argue why the present collection does not belong to the genus Xenocylindrocladium, but phylogenetically, it clusters apart, being more closely related to Curvicladiella, which has hooked, 1-septate, thick-walled, pigmented, verruculose stipe extensions. A Scanning Electron Microscope (SEM) micrograph of Neocalonectria tristaniopsidis can also be seen on the covers of the various issues of Fungal Biology Reviews volume 34, published in 2020. Blast results are supplied as part of the supplementary material.