Original descriptions from type material are provided by Berkeley (1874) and Ellis (1960). Ariyawansa et al. (2015) provided a brief description with the combination into Pseudopithomyces. In this work our colonies (Fig. 8), conidiophore and conidial sizes (–16.4) 22.5–25.8 (–35.1) × (–10.4) 12.4–14.7 (–18) μm, av. 24.4 × 13.6 μm, n = 177 (Figs 6, 12) concur with that of Ellis (18–29 × 10–17) and Ariyawansa (21.5–30.5 × 10–16.5 μm) and are therefore not described here. Other descriptions such as da Cunha et al. (2014) should be treated with caution as their circumscription also included Pse. palmicola (ICMP 24527 = MUCL 9393).

Originally described from the United States, we also record this species from New Zealand, Australia, Belgium, and France (Table S1). Additional geographic distribution countries inferred from GenBank sequence homology are India (MG569510), China (KY977441), France (OW984896, OW988122), Spain (KP899434), Czech Republic (GU566269), and the Netherlands (MH860227). The substrate association seems to be very broad including as a saprobe on various dead plants, dust, and clinical samples.

The type specimen was collected sometime before 1874 from decayed paper in North Carolina, USA. There are no living cultures or DNA sequences from this specimen to fix the typification of this species in a modern context. Ariyawansa et al. (2015), in description of Pseudopithomyces and its type species Pse. chartarum, used the reference culture MUCL 15095 (= ICMP 24528) from bakery dust in Belgium. We accept this circumscription of the species. In their work Ariyawansa et al. (2015) did not select an epitype culture for Pse. chartarum, however an epitype should be selected in the future. Ideally epitypes should come from the same locality and host as the type, but in this case, with the substate being decayed paper, it may be more important for taxonomic stability to fix a well characterised modern culture as the epitype regardless of origin. In the description of Sporidesmium chartarum the authors mention the name “Macrosporium chartarum M.A. Curtis” as a synonym (Fig. 7), this appears to be an unpublished name and different to Macrosporium chartarum (Peck 1873).

The ex-type culture IMI 101184 was invaluable to placing this species in a modern taxonomic concept, prior to this study it had not been sequenced. Here we recombine this species into Pseudopithomyces rather than Pithomyces sensu stricto based on gene sequences. Sequences of ITS alone are likely insufficient to distinguish Pse. cynodontis from Pse. pavgii as the species differed by only 2 bp. However, over the four-gene alignment Pse. cynodontis differs from Pse. pavgii by 202 bp (97.59 % identity), and from Pse. sp. ‘ziziphus AU’ by 187 bp (97.77 % identity). We were unable to get the type culture to sporulate, but Ellis (1965) describes 1–4 longitudinal septa per spore, this differs from Pse. pavgii where longitudinal septa are rare. We received two cultures determined as P. cynodontis, MUCL 54991 = ICMP 24529 from Florida, and BRIP 74113c = ICMP 24722 from Australia. We consider these to be Pse. pavgii and Pse. sp. ‘ziziphus AU’ respectively.

Zambia, Western Province, Mongu airstrip; [15.254315°S, 23.156339°E]. On inflorescence of Cynodon dactylon. 11 Feb. 1963, A. Angus. (holotype IMI 101184; ex-holotype culture: ICMP 24671 = IMI 101184). GenBank: OR691862 (ITS); SRR27202290 (genome).

Here we synonymise the species Pse. palmicola and Pse. pandanicola, both species were typified from Thailand three years apart. We have synonymised these species on the basis of their very similar DNA sequences (Fig. 4). In the four-gene alignment, the two type cultures are 99.95 % identical over 8 452 bp. The published gene sequences (Tibpromma et al. 2018) of the Pse. pandanicola ex-type strain for RPB2 (data not shown) and TEF1 (MH412734 and MH388399) closely match our genome sequences (Fig. S2). There are some differences in the culture morphology across the species (Fig. 9) that we consider natural intraspecific variation. In this study the conidia measured (15.8–) 19.3–23.3 (–34.2) × (9.4–) 13–15.2 (–20) µm, av. 21.6 × 14.0 µm, n = 105 at 25 °C (Figs 6, 12).

A comprehensive description was given by Palm & Stewart (1981). In contrast to many other species in the genus, Pse. pavgii (along with Pse. sacchari) generally lacks longitudinal spore septa.

India, Telangana, Rajendranagar, 17.3125°N, 78.4°E, from seeds of Arachis hypogaea, 3 Jan. 1973, V. Kavindra Nath (holotype IMI 205718).

Our analysis has revealed a putative undescribed species in New Zealand isolated from the leaves of the exotic plant Gladiolus undulatus. We have chosen not to formally describe this as a new species, as Pithomyces gladioli (Zhang & Zhang 2003) was described from the leaves of Gladiolus communis in Jiangxi, China. The “distinctly constricted at transverse septa” conidia described in Pithomyces gladioli are not obvious in Pseudopithomyces sp. ‘gladiolus NZ’ (Fig. 13). The conidial dimensions of P. gladioli are given as 22–33 × 9.5–12 µm (Zhang & Zhang 2003) compared to our cultures that measure (13.2–) 15.8–20.4 (–32.6) × (7.2–) 9.7–12.3 (–19.3) µm, av. 18.3 × 11.1 µm, n = 140 (Fig. S6). Unfortunately, no DNA sequences are available for this species to compare. We will use the tag name Pseudopithomyces sp. ‘gladiolus NZ’ until this can be further investigated.

Colonies – Flat, some sectors can become more floccose. Alternating light grey and olivaceous grey, with dark olivaceous reverse (Fig. 11). Optimum growth temperature at 24 °C, reaching 51 mm in diameter in 6 d. Conidiophores aggregate on agar surface forming sporodochia in 2–3 wk at 25 °C. Mycelium – Hyaline or straw-coloured to brown. Hyaline mycelium is usually thin walled, with septation less common. Pigmented mycelium can be thicker walled, with frequent septation where some areas appear prominently verrucose. Conidiophore – Micronematous (looks like mycelial hyphae). Conidiogenous cells – short, cylindrical and can be flexuous, smooth-walled, faintly pigmented. Secession rhexolytic. Released conidia retain small amount of the conidiogenous cell tissue at the base. Mostly 3.7–8.6 × 2–4 µm though some conidiogenous cells are too short to measure and conidia derived from such cells tend to form a bulbous base, but those with measurable conidiogenous cells can also form this bulbous base which is observed in ICMP 24486. Conidia – Pigmented, turning from straw-coloured to dark olivaceous brown with age. Mostly barrel shaped, obovoid, oblong, ellipsoid, obpyriform, and asymmetric in shape. Some may exhibit a bulbous base. Conidia are initially non-septate and echinulate, and this echinulation becomes less visible as the cell wall becomes darker and thicker. With maturation, the conidia mostly produce 2–3 transverse septa (mostly 3), very rarely 4–5, followed by multiple longitudinal septations (2–5, mostly 2) in each of the middle segments, though longitudinal septation can rarely occur on the apex. (14.4–) 17.3–20.4 (–27.8) × (7.6–) 10–11.8 (–15.4) µm, av. 19.1 ×11 µm, n = 147 at 25 °C (Figs 6, 12).

This species is strongly supported as different from Pse. chartarum and other Pseudopithomyces species through individual gene and genome analyses, and the production of the toxin sporidesmin. The conidia under controlled conditions were slightly smaller (with overlapping ranges) than Pse. palmicola and Pse. chartarum (Fig. 6), but in general conidial morphology (shape, colour, and septation) was indistinguishable from Pse. chartarum and Pse. palmicola (Fig. 12). Searches of literature and global culture collections revealed no earlier description under another name. The type isolate ICMP 24442 was isolated from a dairy farm in 2022 with animals showing signs of FE, this was selected as the type over the original 1958 ‘strain C’ isolate (ICMP 7074) (Percival & Thornton 1958) due to the possibility of changes or attenuation occurring during six decades of storage.

New Zealand, Bay of Plenty, Whakatāne, 37.9511°S 176.7924°E, on dead Poaceae leaf blade, 23 Mar. 2022, M. Gow, Ag031 (holotype PDD 120424, ex-holotype culture ICMP 24442 = CBS 153580 = IMI 507425). GenBank: OR691816 (ITS); SRR27202368 (genome).

The origin of Pse. toxicarius is unknown, although it has caused problematic disease in New Zealand livestock for more than 100 years (di Menna et al. 2009). It is predominantly found on exotic pasture grasses rather than native plants, suggesting an origin outside of New Zealand. We also record this species from Australia, France, South Africa, United Kingdom, United States, and Uruguay (Table S1). Additional host range countries inferred from GenBank sequence homology are, Belgium (OW987887), Canada (KT965035), Colombia (EU272493), Costa Rica (KX499297), and the Netherlands (MH860299).

A description was given by Chary and Ramarao (1972) and Dong et al. (2020). Other material examined: Thailand, Chiang Mai Province, Phrao District; [19.297°N, 99.212°E]. On submerged wood in a stream. 01 Sep. 2017, G.N. Wang, 4.14 (holotype of Pseudoxylomyces aquaticus HKAS 100937; ex-holotype culture KUMCC 17-0312).

This species is only known from aquatic environments in India and Thailand. There are no additional sequences in GenBank to extend this range, although further sampling of aquatic environments globally may reveal a wider distribution.

Here we synonymise the species Pithomyces terricola and Pseudoxylomyces aquaticus and create a new combination for the earlier specific epithet based on the basionym Stemphyliomma terricola. The sequence of ITS for Pithomyces terricola (OR691859) is 100 % identical to that of Pseudoxylomyces aquaticus (NR_171972), and the spore morphologies (Chary & Ramarao 1972, Dong et al. 2020) are very similar.

India, Telangana, Vikarabad; [17.33°N, 77.9°E]. From pond mud (pH 7.7). 8 Aug. 1971, Ch. Manohara Chary and P. Ramarao, No. 6419. (holotype IMI 161793; isotype Osmania University OUF-32; ex-holotype culture ICMP 24668 = IMI 161793). GenBank: OR691859 (ITS); SRR27202293 (genome).