Morphology

Fusarium species were characterised and described using macro- and micromorphological features as defined previously (Leslie & Summerell 2006, Aoki et al. 2013, Sandoval-Denis et al. 2018a, b, 2019). Colony morphology, production of pigments and odours were documented on PDA after incubation for 7 d at 25 °C in darkness, under continuous fluorescent light and using a 12/12 h cool fluorescent light/dark cycle. Colony growth rates were also determined on PDA by inoculating overgrown 5 mm agar blocks, obtained from 7-d-old cultures growing on synthetic nutrient poor agar (SNA; Nirenberg 1976) and incubated at 10–35 °C with 5 °C intervals in darkness. Colonies were measured daily over a 7-d-period in four perpendicular directions. Colony morphologies were captured with a Sony NEX-5N camera. Unless otherwise noted, micromorphological observations were made using water as mounting medium from fungal structures grown on carnation leaf agar (CLA; Fisher et al. 1982), incubated at 25 °C under a 12/12 h near-ultraviolet light (nuv)/dark cycle (Fisher et al. 1982, Leslie & Summerell 2006). Colony colour codes were determined following the protocols of Kornerup & Wanscher (1967). All measurements and images were taken using a Nikon Eclipse Ni compound and SMZ18 dissecting microscopes (Nikon, Japan), equipped with a Nikon DS-Ri camera using the NIS-Elements BR imaging software. Up to 50 measurements were made for the conidia and other morphological structures where these were available and maximum – minimum values with averages were determined. Photographic plates were prepared in Affinity Photo v. 1.7.3 (Serif (Europe) Ltd, Nottingham, UK).

Taxonomy

In this section, Latin binomials are provided for the three novel phylospecies resolved in this study, namely F. chinhoyiense, F. longicornicola and F. pilosicola spp. nov. In addition, epitypes are designated for F. anthophilum, F. lactis, F. proliferatum, F. sacchari, F. succisae and F. verticillioides. Fusarium acutatum and F. ophioides are validated. Furthermore, a neotype is designated for F. subglutinans and an emended description provided for F. annulatum.

Fusarium acutatum Nirenberg & O’Donnell, sp. nov. — MycoBank MB 838782

Synonym. Fusarium acutatum Nirenberg & O’Donnell, Mycologia 90: 435. 1998, nom. inval., Art. 40.1.

Etymology. Named for the acute apical cell of the sporodochial conidia produced by this species.

Typus. INDIA, unknown substrate, 1995, S.N. Smith (holotype B 70 0001695, designated here, culture ex-type BBA 69580 = NRRL 13309 = FRC 0-1117 = CBS 402.97 = IMI 376110).

For diagnosis — See Nirenberg & O’Donnell, Mycologia 90: 435. 1998.

Notes — Fusarium acutatum was isolated from Aphididae (Hemiptera) on Triticum sp. (wheat) from Pakistan and Cajanus sp. from India (Nirenberg & O’Donnell 1998, Leslie & Summerell 2006). It is known to produce beauvericin, enniatins and moniliformin (Munkvold 2017). Although this species was introduced by Nirenberg & O’Donnell (1998), it was invalidly described (Index of Fungi 6: 435, 1999). In the protologue for F. acutatum (Nirenberg & O’Donnell 1998) no reference was made to the specimen or gathering (Art. 40.1) for the holotype. Therefore, we validate the species here.

Fusarium annulatum Bugnic., Rev. Gén. Bot. 59: 17. 1952 — Fig. 2

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Fig. 2

Fusarium annulatum (a, h, j–l. CBS 258.54^T; b, c, g, i, m. CBS 531.96; d, f. CBS 139379; e. CBS 134.95; n. CBS 143601). a–b. Sporodochia formed on the surface of carnation leaves; c–h. aerial conidiophores and conidiogenous cells; i–j. aerial conidia; k. sporodochial conidiophores and conidiogenous cells; l–n. sporodochial conidia. — Scale bars: a–d = 50 μm; all others = 10 μm (scale bar in l also applies to m and n).

Typus. NEW CALEDONIA, grain of Oryza sativa, F. Bugnicourt (holotype IMI 202878, ex-type culture CBS 258.54 = BBA 63629 = IMI 202878 = MUCL 8059 = NRRL 13619).

Description & Illustrations — (as F. proliferatum) Nirenberg (1976), Gerlach & Nirenberg (1982), Nelson et al. (1983), Nirenberg & O’Donnell (1998), Domsch et al. (2007).

Notes — Fusarium annulatum has been extensively studied in the past under the name F. proliferatum, a segregate of Fusarium moniliforme s.lat. (Seifert et al. 2003). The name Fusarium proliferatum, however, is here assigned to a distinct phylogenetic clade based on an isolate collected from the type location and substrate of that species (see notes under F. proliferatum and in Discussion). Fusarium annulatum is a morphologically and phylogenetically diverse species, common in tropical and temperate zones (Domsch et al. 2007), with more than 200 plant host species reported to date. This species is a well-known pathogen of diverse crops worldwide (as F. proliferatum, Farr & Rossman 2021), and has been implicated in human infections, particularly on immunocompromised patients (Summerbell et al. 1988, O’Donnell et al. 2007). Fusarium annulatum is characterised by sympodially proliferating conidiophores producing mono- and polyphialides, and clavate microconidia with truncate bases grouped in moderately long chains and false heads. Chlamydospores are absent. Sporodochia and sporodochial conidia are typical for this species complex, but are seldom produced or can be poorly developed, thus being easily overlooked. According to Gerlach & Nirenberg (1982), the ex-type strain of F. annulatum (CBS 258.54) failed to produce sporodochia; however, as determined here, this strain will produce typical sporodochia under the culture conditions we employed in this study. Unlike other members of this clade, this strain of F. annulatum is unique by producing strongly curved macroconidia (Fig. 2). Nevertheless, Nelson et al. (1983) showed that straight sporodochial conidia are also produced by this strain, which were also observed in this study. Other strains of F. annulatum studied to date produce predominantly straight macroconidia.

Fusarium anthophilum (A. Braun) Wollenw., Ann. Mycol. 15: 14. 1917

Basionym. Fusisporium anthophilum A. Braun, in Rabenhorst, Fung. Europ. Exs.: no. 1964. 1875.

Synonyms. Fusarium moniliforme var. anthophilum (A. Braun) Wollenw., Fusaria Autogr. Delin. 3: 975. 1930.

Fusarium tricinctum var. anthophilum (A. Braun) Bilaĭ, Fusarii (Biologija I sistematika): 251. 1955.

Fusarium sporotrichiella var. anthophilum (A. Braun) Bilaĭ, Mikrobiol. Zhurn. 49: 7. 1987.

Fusarium sanguineum var. pallidius Sherb., Mem. Cornell Univ. Agric. Exp. Sta. 6: 196. 1915.

Fusarium wollenweberi Raillo, Fungi of the genus Fusarium: 189. 1950.

Typus. GERMANY, Berchtesgaden, from Succisa pratensis, 1 Sept. 1874, A. Braun (lectotype of Fusisporium anthophilum, MBT 10000411, exsiccate Rabenhorst, Fungi europaei nr. 1964 in B, designated here); Berlin, on Euphorbia pulcherrima, 1975, H. Nirenberg (epitype, MBT 10000412, CBS 222.76 (preserved as metabolically inactive culture), designated here, culture ex-epitype CBS 222.76 = BBA 63270 = IMI 196084 = IMI 202880 = NRRL 22943 = NRRL 25216).

Description & Illustrations — See Wollenweber & Reinking (1935), Nirenberg (1976), Gerlach & Nirenberg (1982), Nelson et al. (1983), Leslie & Summerell (2006).

Notes — Nirenberg (1976) studied the type material from Braun (1875) and found that isolate CBS 222.76 agreed with the type collection in its morphology and locality. This was further supported by Gerlach & Nirenberg (1982). Therefore, in this study the illustration by Braun (1875) is designated as lectotype, and CBS 222.76 is designated as epitype for F. anthophilum.

Fusarium chinhoyiense Yilmaz & Crous, sp. nov. — MycoBank MB 838763; Fig. 3

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Fig. 3

Fusarium chinhoyiense sp. nov. (NRRL 25221^T). a. Colonies in PDA after 7 d at 25 °C light, dark and nuv (from left to right), respectively; b. sporodochia formed on the surface of carnation leaves; c. aerial conidia; d–e. aerial conidiophores and phialides; f. sporodochial conidiophores and phialides; g. sporodochial conidia. — Scale bars: c–g = 10 μm.

Etymology. Name refers to Chinhoyi, the region, from which the ex-type strain of this fungus was collected.

Typus. ZIMBABWE, Chinhoyi, from Zea mays, unknown date and collector (holotype PREM 63215, designated here, culture ex-type NRRL 25221 = BBA 69031 = IMI 375355 = Frank 5bCn8 = DAOM 225149 = CMWF1187 = NY007.I2).

Conidiophores on CLA borne on the aerial mycelium straight or flexuous, erect or prostrate, smooth- and thin-walled; conidiogenous cells mono- and polyphialidic, subcylindrical, smooth- and thin-walled, 11–25 × 2–3.5 μm, without periclinal thickening; microconidia formed on aerial conidiophores, hyaline, oval to ellipsoidal, smooth- and thin-walled, aseptate, (4.5–)5–9(–11) × 2.5–3.5 μm (av. 7 × 3 μm), clustering in discrete false heads at the phialide tips. Sporodochia white to pale yellow, often somewhat translucent, formed abundantly on the surface of carnation leaves and on the agar surface, often covered with aerial mycelium. Sporodochial conidiophores densely aggregated, irregularly and verticillately branched, typically producing dense whorls of terminal phialides; sporodochial conidiogenous cells doliiform to subcylindrical, (8–)10–14(–18) × 2.5–4 μm (av. 12 × 3 μm), smooth- and thin-walled, with periclinal thickening and an inconspicuous apical collarette. Sporodochial conidia straight to falcate, tapering toward the basal part, robust, moderately curved and slender; apical cell more or less equally sized as the adjacent cell, blunt to slightly papillate; basal cell distinctly foot-shaped or barely notched, 2–5-septate, hyaline, thin- and smooth-walled, 2-septate conidia: (20–)22–27(–31) × 2–4 μm (av. 35 × 3 μm; n = 3); 3-septate conidia: (23–)27–38(–42) × 3–4 μm (av. 34 × 4 μm); 4-septate conidia: 40.5 × 3 μm (n = 1). Chlamydospores absent.

Culture characteristics — Colonies on PDA growing in the dark with an average radial growth rate of 5.8–7.3(–7.7–8.5) mm/d and reaching 50–60 mm diam at 25 °C, optimal 25–30 °C (after 7 d). Surface white, flat with abundant aerial mycelia on PDA incubated in dark. Reverse pale yellow (1A2), becoming dark blue at the centre with age. Odour absent. Sporodochia abundant on PDA incubated on constant nuv light.

Additional material examined. SOUTH AFRICA, from soil, Feb. 2018, C.M. Visagie, NY 001.B5.

Notes — This species is phylogenetically closely related to F. mundagurra isolated from soil in Australia (Laurence et al. 2016) and the recently described F. caapi isolated from Brachiaria brizantha from Brazil (Costa et al. 2021). Fusarium mundagurra has 1-septate microconidia and both F. mundagurra and F. caapi abundantly produce chlamydospores in culture, whereas F. chinhoyiense has aseptate microconidia and lacks chlamydospores. Fusarium chinhoyiense shares the common morphological features of those in FFSC, such as lack of chlamydospores, and oval to clavate microconidia. Moreover, microconidia are produced in relatively short chains from phialides forming false heads, somewhat resembling those produced by F. oxysporum rather than most members of the FFSC (Leslie & Summerell 2006). However, F. chinhoyiense is distinguished from F. oxysporum by the absence of chlamydospores. Although F. chinhoyiense also resembles F. subglutinans, the latter species is distinct in producing sterile, coiled hyphae.

Fusarium lactis Pirotta, Arch. Lab. Bot. Crittog. Univ. Pavia 2 & 3: 316. 1879 — Fig. 4

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Fig. 4

Lectotype of Fusarium lactis (Pirotta & Riboni 1879).

Synonyms. ?Fusarium pyrinum Schwein., Trans. Amer. Philos. Soc., n.s. 4: 302. 1834.

?Fusarium apiogenum Sacc., Syll. Fung. 4: 717. 1886.

Fusarium rubrum Parav., Ann. Mycol. 16: 311. 1918.

Typus. ITALY, Pavia, on clotted milk, 1879, R. Pirotta & G. Riboni (lectotype, MBT 10000413, Arch. Lab. Bot. Crittog. Univ. Pavia 2 & 3, t. 21, f. 1–6, designated here). – USA, California, on Ficus carica, 1994, T. Michailides (epitype, MBT 10000414, B 70 0001686, designated here, culture ex-epitype BBA 68590 = NRRL 25200 = CBS 411.97 = IMI 375351).

Description & Illustrations — See Nirenberg & O‘Donnell (1998), Leslie & Summerell (2006).

Notes — As the type specimen of F. lactis could not be located in PAV or PAD (Herbarium Saccardo), Nirenberg & O’Donnell (1998) neotypified the species based on NRRL 25200 (= BBA 68590 = CBS 411.97 = IMI 375351 = DAOM 225145) which was isolated from Ficus carica in the USA. However, the neotypification of F. lactis by Nirenberg & O’Donnell (1998) was not Code compliant (ICN; Art. 9.13) as an illustration was provided along with the original protologue. Therefore, the original illustration is designated as the lectotype and the neotype of Nirenberg & O‘Donnell (1998) is designated as an epitype.

Fusarium longicornicola Sand.-Den., Yilmaz & Crous, sp. nov. — MycoBank MB 838764; Fig. 5

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Fig. 5

Fusarium longicornicola sp. nov. (NRRL 52706^T). a. Colonies in PDA after 7 d at 25 °C light, dark and nuv (from left to right), respectively; b–c. sporodochia formed on the surface of carnation leaves; d–g. aerial conidiophores and phialides; h. aerial conidia; i–j. sporodochial conidiophores and phialides; k. sporodochial conidia. — Scale bars: d–k = 10 μm.

Etymology. Name refers to the substrate, Aiolopus longicornis, from which the ex-type strain of this fungus was isolated.

Typus. ETHIOPIA, Kobo, Welo, from a grasshopper (Aiolopus longicornis), unknown date and collector (holotype CBS H-24661, designated here, culture ex-type CBS 147247 = NRRL 52706 = ARSEF 6455).

Conidiophores on CLA produced laterally and abundantly on aerial and substrate mycelium, straight or flexuous, smooth- and thin-walled, simple or loosely irregularly and verticillately branched, up to 95 μm tall, copiously proliferating percurrently, or reduced to conidiogenous cells borne laterally on hyphae; conidiogenous cells mono- and polyphialidic, subulate to subcylindrical, smooth- and thin-walled, 11–22.5 μm long, 2.5–4.5 μm at the widest point, periclinal thickening inconspicuous or absent; microconidia formed sparsely, hyaline, ellipsoidal, reniform to subclavate, smooth- and thin-walled, 0(–1)-septate, 5–9.5(–14) × 2–3.5 μm (av. 7.5 × 2.5 μm), clustering in discrete false heads at the phialide tips. Sporodochia pale to bright orange, formed on the surface of carnation leaves. Sporodochial conidiophores densely aggregated, irregularly and verticillately branched, bearing single terminal phialides or groups of 2–3 phialides; sporodochial conidiogenous cells monophialidic, subulate to subcylindrical, 10–16 × 2.5–4 μm, smooth- and thin-walled, with conspicuous periclinal thickening and often with a short apical collarette. Sporodochial conidia falcate, almost straight to moderately dorsiventrally curved, tapering toward the basal part; apical cell blunt to hooked; basal cell barely to distinctly notched, 1–3-septate, hyaline, thin- and smooth-walled, 1-septate conidia: (14.5–)16–21(–23) × 2.5–4 μm (av. 18.7 × 3.2 μm); 2-septate conidia: (18.5–)20–25.5(–28) × 3–4 μm (av. 22.7 × 3.4 μm); 3-septate conidia: (16.5–)21.5–29.5 × 3–5 μm (av. 25.3 × 3.7 μm). Chlamydospores absent.

Culture characteristics — Colonies on PDA growing in the dark with an average radial growth rate of 3–5.7 mm/d and reaching 42–80 mm diam at 25 °C, optimal 20–30 °C after 7 d. Surface velvety to floccose, grey-magenta (13E6–14D4) to red-grey (9B2) towards margin, flat, filamentous to rhizoid with filiform margin. Reverse red-brown (9D6) to red-grey (12E2). Odour absent to mouldy.

Additional isolates examined. ETHIOPIA, Kobo, Welo, from Aiolopus longicornis, unknown date and collector, CBS 147248 = NRRL 52712 = ARSEF 6451; CBS 147249 = NRRL 52713 = ARSEF 6446.

Notes — Pfenning et al. (2019) recently redefined and fixed the typification of F. udum to a well-delimited phylogenetic clade and distinct mating population in the FFSC. Additional isolates previously assigned to F. udum were found not to belong to the current phylogenetic and biological circumscription of the species, most likely representing distinct species. Our phylogenetic and morphological results confirm those observations. The three insecticolous isolates here ascribed to F. longicornicola cluster in a well-differentiated and supported phylogenetic lineage. Apart from its different host association, F. longicornicola differs morphologically from F. udum. The latter species produces only monophialides on its aerial conidiophores, cream coloured sporodochial conidial masses bearing longer and more regularly septate sporodochial conidia, and abundant chlamydospores. The two closest phylogenetic relatives of F. longicornicola, F. phyllophilum and F. xylarioides, are both morphologically distinguishable from the former species. Fusarium phyllophilum mainly differs by lacking sporodochia, although, 5-septate sporodochial conidia are rarely observed in the latter species. Additionally, F. longicornicola differs from F. phyllophilum by its ellipsoidal and reniform microconidia (vs clavate in F. phyllophilum) and ecological traits (insecticolous vs foliicolous in F. phyllophilum; Nirenberg & O’Donnell (1998), Leslie & Summerell (2006)). Differences between F. longicornicola and F. xylarioides are more striking, as the latter species, which is a vascular pathogen of Coffea sp., produces aseptate, allantoid microconidia formed on monophialides only, strongly curved sporodochial conidia and chlamydospores (Gerlach & Nirenberg 1982).

Fusarium ophioides A. Jacobs, T.A. Cout. & Marasas, sp. nov. — MycoBank MB 838783; Fig. 6

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Fig. 6

Fusarium ophioides (CBS 118512^T). a. Colonies in PDA after 7 d at 25 °C light, dark and nuv (from left to right), respectively; b–c. sporodochia formed on the surface of carnation leaves; d–e. sporodochial conidiophores and phialides; f–j. aerial conidiophores and conidiogenous cells; k–l. microconidia; m. mesoconidia; n. serpentine hyphae (adapted from Jacobs 2010); o. sporodochial conidia. — Scale bars: d, f–g = 50 μm; k, n = 5 μm; all others = 10 μm.

Synonym. Fusarium ophioides (as ‘ophiodes’) A. Jacobs, T.A. Cout. & Marasas, Taxonomy of species within the Gibberella fujikuroi complex: 83. 2010, nom. inval. Art 30.9.

Etymology. The specific epithet is from the Greek ophis that means snake and refers to the serpentine hyphae produced by this species in culture.

Typus. SOUTH AFRICA, Mpumulanga, Ngodwana, from Panicum maximum, G. Kemp (holotype CBS H-24659, designated here, culture ex-type CBS 118512 = CMW 18681 = FCC 2979 = FCC 2980 = MRC 6744).

Conidiophores on CLA produced prostrate on substrate mycelium and laterally on aerial mycelium, straight or flexuous, smooth- and thin-walled, rarely simple, commonly sympodially to irregularly branched, up to 190 μm tall, proliferating percurrently; phialides mono- and polyphialidic, subulate to cylindrical, smooth- and thin-walled, 6.5–22.5 μm long, 2.5–4 μm at the widest point, periclinal thickening and collarettes inconspicuous to absent; microconidia hyaline, obovate, ellipsoidal to short falcate, smooth- and thin-walled, 0(–1)-septate, (5–)6.5–15(–20.5) × 2–4.5(–5.5) μm (av. 11 × 3.3 μm), clustering in false heads at the tip of phialides. Mesoconidia falcate, almost straight to moderately dorsiventrally curved, tapering toward the apical part; apical cell pyramidal to slightly hooked; basal cell rounded to barely notched 2–5-septate, hyaline, thin- and smooth-walled, 2-septate conidia: (19.5–)20–27(–28) × 3.5–4.5(–5.5) μm (av. 23.9 × 4.3 μm); 3-septate conidia: (29–)33.5–47(–60) × 3–4.5(–5.5) μm (av. 40.4 × 3.9 μm); 4-septate conidia: (45–)47.5–59.5 × 3–4.5 μm (av. 53.2 × 3.8 μm); 5-septate conidia: (56–)58–66.5 × 3–4.5 μm (av. 62.3 × 3.4 μm), formed abundantly on polyblastic conidiogenous cells on aerial mycelium and conidiophores. Sporodochia luteous to orange, formed on the surface of carnation leaves. Sporodochial conidiophores densely aggregated, irregularly and verticillately branched, bearing single terminal phialides or groups of up to four phialides; sporodochial conidiogenous cells monophialidic, subulate to subcylindrical, 10.5–21 × 2.5–4 μm, smooth- and thin-walled periclinal thickening and collarettes inconspicuous to absent. Sporodochial conidia falcate, almost straight to moderately dorsiventrally curved tapering toward the basal part; apical cell elongated to hooked; basal cell barely to distinctly notched, 2–5-septate, hyaline, thin- and smooth-walled, 2-septate conidia: 23–25 × 3.5–4 μm (av. 24.1 × 3.9 μm); 3-septate conidia: (30.5–)37–54(–60.5) × 3–5 μm (av. 45.3 × 4.1 μm); 4-septate conidia: (49–)53.5–65(–69.5) × 3.5–5 μm (av. 59.2 × 4.3 μm); 5-septate conidia: (53.5–)57–70(–75.5) × 3.5–5.5 μm (av. 63.5 × 4.4 μm). Chlamydospores absent. Sterile, curved hyphae with alternating curvature direction (serpentine hyphae) abundantly formed on the surface of CLA and SNA.

Culture characteristics — Colonies on PDA growing in the dark with an average radial growth rate of 3–5.4 mm/d and reaching 42–76 mm diam at 25 °C, optimal 25–30 °C after 7 d. Surface brown-red (10D8) to violet brown (11E5), velvety to wholly, flat with filiform margin. Reverse grey-ruby (12D4–12E6). Odour absent.

Additional isolates examined. SOUTH AFRICA, Mpumulanga, Ngodwana, from Phragmites mauritianus, G. Kemp, CBS 118509 = CMW 18678 = MRC 6748 = FCC 1092; from Panicum maximum, G. Kemp, CBS 118510 = CMW 18679 = MRC 6747 = FCC 1093, CBS 118511 = CMW 18679 = MRC 6747 = FCC 1093, CBS 118513 = CMW 18682 = MRC 6745 = FCC 2997, CBS 118514 = CMW 18683 = MRC 6750 = FCC 2972, CBS 118515 = CMW 18684 = MRC 6754 = FCC 2974.

Notes — Strains assigned to F. ophioides were isolated during a survey of South African grasses. The species was invalidly described in a doctoral thesis lacking an ISSN number (Art. 30.9). Here, we validate the name based on its original material deposited at the CBS (Jacobs 2010). Moreover, a morphological description is included to account for previously undocumented features, i.e., sporodochia and sporodochial conidia, and the nature of the aerial falcate, multiseptate conidia, here found to emerge singly from well-developed, predominately polyblastic and commonly sympodially proliferating conidiogenous cells, conforming to the description of mesoconidia sensu Pascoe (1990). For additional images and discussions about pathogenicity, mating behaviour and closely related taxa see Jacobs (2010).

Fusarium pilosicola Yilmaz, B.D. Wingf. & Crous, sp. nov. — MycoBank MB 838766; Fig. 7

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Fig. 7

Fusarium pilosicola sp. nov. (NRRL 29124^T). a. Colonies in PDA after 7 d at 25 °C light, dark and nuv (from left to right), respectively; b. sporodochia formed on the surface of carnation leaves; c. aerial conidia; d–e. aerial conidiophores and phialides; f. sporodochial conidiophores and phialides; g. sporodochial conidia. — Scale bars: c–g = 10 μm.

Etymology. Referring to the substrate, Bidens pilosa, from which the ex-type strain of this fungus was collected.

Typus. USA, Florida, from Bidens pilosa, unknown date and collector (holotype PREM 63216, designated here, culture ex-type NRRL 29124 = CMWF 1183 = NY007.H7).

Conidiophores on CLA sparse on aerial mycelium, straight or flexuous, erect or prostrate, smooth- and thin-walled, commonly unbranched, up to 90 μm tall or reduced to conidiogenous cells borne laterally on hyphae; conidiogenous cells mono- and polyphialidic, subcylindrical, smooth- and thin-walled, 8.5–24 × 2–3.5 μm, without periclinal thickening; microconidia formed on aerial conidiophores, hyaline, oval to ellipsoidal to ovoid, smooth- and thin-walled, mostly aseptate, (5.5–)7–12 × 2–4 μm (av. 9 × 3 μm), rarely 1-septate, 16–19 × 3–4 μm (av. 18 × 4 μm; n = 2), clustering in discrete false heads at the phialide tips. Sporodochia orange or sometimes pale yellow, often somewhat translucent, formed abundantly on the surface of carnation leaves. Sporodochial conidiophores densely aggregated, irregularly and verticillately branched, typically producing dense whorls of 2–4 phialides; sporodochial conidiogenous cells elongated subulate to subcylindrical, 11–24 × 3–4 μm, smooth- and thin-walled, with periclinal thickening and an inconspicuous apical collarette. Sporodochial conidia straight to falcate, tapering toward the basal part, robust, slightly curved and slender or sometimes strongly curved; apical cell papillate; basal cell foot-shaped, (3–)4(–5)-septate, hyaline, thin- and smooth-walled, 3-septate conidia: (33–)44–56 × 4.5–5.5 μm (av. 48.6 × 5 μm; n = 4); 4-septate conidia: (48–)50–70(–75) × 4–6.5 μm (av. 59 × 5 μm); 5-septate conidia: 55–70(–80) × 4–5(–6) μm (av. 66.5 × 5 μm; n = 2). Chlamydospores absent.

Culture characteristics — Colonies on PDA growing in the dark with an average radial growth rate of (6.2–)7.2–7.8 mm/d and reaching 45–55 mm diam at 25 °C, optimal 25 °C after 7 d. Surface floccose, abundantly sporulating on PDA, white interspersed with purple mycelia at 25 °C (orange-pink under light and nuv light). Reverse with dark blue (20F4) centre fading into yellow-white (4A2) to orange-white (5A2) in dark. Odour absent.

Additional isolate examined. USA, Florida, from Bidens pilosa, unknown date and collector, NRRL 29123 = CMWF 1189= NY 007.I4.

Notes — Fusarium pilosicola is a relatively slow-growing species. This species is phylogenetically closely related to F. circinatum and also resembles F. circinatum and F. subglutinans by producing microconidia in false heads. However, F. circinatum is characterised by the formation of sterile, coiled hyphae on SNA and sometimes on CLA, whereas this was not observed for F. pilosicola. On PDA F. subglutinans produces shades of purple pigment ranging from a dark purple to nearly black, whereas F. pilosicola lacks purple pigmentation.

Fusarium proliferatum (Matsush.) Nirenberg ex Gerlach & Nirenberg, Mitt. Biol. Bundesanst. Land-Forstw. 209: 309. 1982 — Fig. 8, ​,99

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Fig. 8

Lectotype of Fusarium proliferatum (Matsushima 1971).

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Fig. 9

Fusarium proliferatum (CBS 480.96^ET). a. Colonies in PDA after 7 d at 25 °C light, dark and nuv (from left to right), respectively; b. sporodochia formed on the surface of carnation leaves; c. aerial conidia; d–e. aerial conidiophores and phialides; f–g. sporodochial conidiophores and phialides; h. sporodochial conidia. — Scale bars: c–h = 10 μm.

Basionym. Cephalosporium proliferatum Matsush., Microfungi of the Solomon Islands and Papua-New Guinea: 11. 1971.

Synonyms. Fusarium proliferatum (Matsush.) Nirenberg, Mitt. Biol. Bundesanst. Land-Forstw. 169: 38. 1976, nom. inval., Art. 41.3.

Fusarium proliferatum var. minus Nirenberg, Mitt. Biol. Bundesanst. Land-Forstw. 169: 43. 1976, nom. inval., Art. 41.3.

Typus. PAPUA NEW GUINEA, forest soil, Matsushima (lectotype of Cephalosporium proliferatum, MBT 10000437, Matsushima T. 1971. Microfungi of the Solomon Islands and Papua New Guinea: 11, f. 121.2, designated here); Papua New Guinea, Morobe province, Bulolo, forest soil, Nov. 1995, collected by A. Aptroot and isolated by A. van Iperen (epitype, MBT 10000438, CBS 480.96 (metabolically inactive) designated here; cultures ex-epitype CBS 480.96 = IAM 14682 = NRRL 26427 = NY007.B6).

Conidiophores on CLA difficult to locate, sparse on the aerial mycelium, straight or flexuous, erect, smooth- and thin-walled, commonly unbranched or irregularly branched, up to 85 μm tall or reduced to conidiogenous cells borne laterally on hyphae; conidiogenous cells mono- and polyphialidic, subulate, to subcylindrical, smooth- and thin-walled, 7.5–18 × 2–3 μm, without periclinal thickening; microconidia formed sparsely, hyaline, ovoid to pear-shaped, smooth- and thin-walled, aseptate, (5–)6–11(–13) × 2–3(–4) μm (av. 8.5 × 3 μm), rarely 1-septate (11.5–)13–14(–17.5) × 2.5–3.5 μm (av. 14 × 3 μm; n = 3), clustering in discrete false heads at the tip of phialides. Sporodochia white to pale yellow, often somewhat translucent, formed on the surface of carnation leaves. Sporodochial conidiophores densely aggregated, irregularly and verticillately branched, typically producing dense whorls of 2–4 phialides; sporodochial conidiogenous cells monophialidic and polyphialidic, subulate to doliiform, 5.5–18 × 2.5–5 μm, smooth- and thin-walled, with periclinal thickening and an inconspicuous apical collarette. Sporodochial conidia straight to falcate, tapering toward the basal part, robust, moderately curved and slender and sometimes strongly curved; apical cell papillate; basal cell foot-shaped to barely notched, (1–)3(–4)-septate, hyaline, thin- and smooth-walled, 1-septate conidia: (16.5–)20–30(–36.5) × (1.5–)2–3(–4) μm (av. 24 × 3 μm; n = 7); 2-septate conidia: 26–28 × 2–4 μm (n = 1); 3-septate conidia: (28–)30–50(–56) × 2.5–4.5 μm (av. 42.3 × 3.3 μm); 4-septate conidia: 46.5–60.5 × 3–4 μm (n = 2). Chlamydospores absent.

Culture characteristics — Colonies on PDA growing in the dark with an average radial growth rate of 10.3–10.7 mm/d and reaching 69–71 mm diam at 25 °C, optimal 25–30 °C after 7 d. Surface floccose, white to pale pink, abundantly sporulating on PDA incubated in the dark. Reverse with pale greyish ruby (12C7) centre fading into greyish rose (11B3), becoming dark violet to blue at centre with age. Odour absent.

Notes — For original descriptions and illustrations, see Matsushima (1971), Nirenberg (1976) and Gerlach & Nirenberg (1982). Fusarium proliferatum was originally described as Cephalosporium proliferatum by Matsushima and isolated from soil from Papua New Guinea (Matsushima 1971). When Matsushima described the species, it was based on pear-shaped (pyriform) microconidia and striking polyphialides (Fig. 8). The culture (MFC-2683) did not produce any sporodochial conidia. Gams & Lacey (1972) made the assumption that C. proliferatum probably belonged to Fusarium sect. Liseola. In 1976, Nirenberg had the opportunity to examine the ex-type specimen of F. proliferatum (Nirenberg 1976), but also failed to observe any sporodochial conidia. Although isolate NRRL 13289 was preserved in the NRRL collection as ‘type’ of F. proliferatum, it was derived from NRRL 6322 (MRC 1784 = ATCC 76097 = FRC M-1138) which was originally isolated from cotton collected in North Carolina (Marasas et al. 1988). As shown in our results, NRRL 13289 belongs to the F. fujikuroi clade. As there is no living ex-type strain available to serve as phylogenetic anchor for F. proliferatum, we designate the original illustration as lectotype, and CBS 480.96 (same substrate, location and morphology, and deposited in 1995 as F. proliferatum) as epitype for F. proliferatum.

Fusarium sacchari (E.J. Butler) W. Gams, Cephalosporium-artige Schimmelpilze: 218. 1971 — Fig. 10

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Fig. 10

Lectotype of Fusarium sacchari (Butler & Khan 1913).

Basionym. Cephalosporium sacchari E.J. Butler, Mem. Dept. Agric. India, Bot. Ser. 6: 185. 1913.

Synonyms. Fusarium neoceras Wollenw. & Reinking, Phytopathology 15: 164. 1925.

Gibberella sacchari Summerell & J.F. Leslie, Mycologia 97: 719. 2005, nom. illeg., Art. 53.1, non Gibberella sacchari Speg. 1896.

Fusarium desaboruense N. Maryani et al., Persoonia 43: 59. 2019.

Typus. INDIA, from culms of Saccharum officinarum, E.J. Butler (lectotype of Cephalosporium sacchari, MBT 10000416, Mem. Dept. Agric. India, Bot. Ser. 6: 185, pl. II, f. 1–13 (1913), designated here); from Saccharum officinarum, 1975, Schaft (epitype, MBT 10000417, CBS 223.76 (preserved as metabolically inactive culture), designated here, culture ex-epitype CBS 223.76 = BBA 63340 = DAOM 225138 = IMI 202881 = NRRL 13999).

Description & Illustrations — See Gams (1971), Gerlach & Nirenberg (1982), Leslie et al. (2005), Leslie & Summerell (2006).

Notes — Because the original type specimen is no longer available, Leslie et al. (2005) neotypified F. sacchari based on isolate KSU B-03852 (ATCC 201264 = FGSC 7610 = FRC M6865). However, in the protologue of F. sacchari, Butler & Khan (1913) did include an illustration which is designated here as lectotype. This supersedes the neotype (Art. 9.13) designation by Leslie et al. (2005). Therefore, CBS 223.76, isolated from Saccharum officinarum collected in India, is designated here as epitype. Additionally, this ex-epitype isolate has been used as the representative isolate of F. sacchari in recent phylogenetic studies on the F. fujikuroi species complex (O’Donnell et al. 1998, 2013, Herron et al. 2015). The inclusion of a larger sampling of F. sacchari isolates for the multigene phylogenies in this study clearly resolved F. desaboruense (Maryani et al. 2019b), isolated from banana collected in Indonesia, within the F. sacchari clade. Therefore, we consider F. desaboruense as a synonym of F. sacchari. The molecular data also showed that F. sacchari and F. neoceras are conspecific, therefore we synonymize F. neoceras with F. sacchari.

Fusarium subglutinans (Wollenw. & Reinking) P.E. Nelson et al., Fusarium species: An illustrated manual for identification: 135. 1983 — Fig. 11

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Fig. 11

Fusarium subglutinans (CBS 747.97^ET). a. Colonies in PDA after 7 d at 25 °C light, dark and nuv (from left to right), respectively; b. sporodochia formed on the surface of carnation leaves; c. aerial conidia; d–e. aerial conidia, conidiophores and phialides; f. sporodochial conidiophores and phialides; g. sporodochial conidia. — Scale bars: c–g = 10 μm.

Basionym. Fusarium moniliforme var. subglutinans Wollenw. & Reinking, Phytopathology 15: 163. 1925.

Synonyms. Gibberella fujikuroi var. subglutinans (Wollenw. & Reinking) E.T. Edwards, Agric. Gaz. New South Wales 44: 895. 1933, Art. F.8.1, Note 2, Exs. 2.

Fusarium moniliforme f. subglutinans (Wollenw. & Reinking) C. Moreau, Rev. Mycol. (Paris) 17: 23. 1952.

Fusarium sacchari var. subglutinans (Wollenw. & Reinking) Nirenberg, Mitt. Biol. Bundesanst. Land-Forstw. 169: 53. 1976.

Gibberella subglutinans (Wollenw. & Reinking) P.E. Nelson et al., Fusarium species: An illustrated manual for identification: 135. 1983.

Typus. USA, Illinois, St. Elmo, from Zea mays, date unknown, J.F. Leslie (neotype of Fusarium moniliforme var. subglutinans MBT 10000418, CBS 747.97 (preserved as metabolically inactive culture), designated here, culture ex-neotype CBS 747.97 = BBA 62451 = DAOM 225141 = FRC M-36 = MRC 8554 = NRRL 22016 = NRRL 22114).

Description & Illustrations — See Booth (1971), Nirenberg (1976, 1981), Nelson et al. (1983), Pascoe (1990), Leslie & Summerell (2006).

Notes — No living type material or holotype specimen is available for F. subglutinans. Therefore, CBS 747.97 (= NRRL 22016) isolated from corn in the USA, is designated as the neotype for this species. Historically, this strain has been used as representative of F. subglutinans in various phylogenetic studies (Zeller et al. 2003, O’Donnell et al. 2013, Herron et al. 2015), and thus we conserve the modern interpretation of this species.

Fusarium succisae J. Schröt. ex Sacc., Syll. Fung. 10: 724. 1892

Synonym. Fusisporium succisae J. Schröt., Hedwigia 13: 180. 1874, nom. inval., Art. 36.1(a).

Typus. GERMANY, Bavaria, Borussia, from Succisa pratensis, 1875, de Thuemen (lectotype, MBT 10000419, ILL00076313 (Thuemen, Mycoth. Univ. nr. 675) designated here); from flower of Succisa pratensis, 1973, H. Nirenberg (epitype, MBT 10000420, IMI 202876, designated here, culture ex-epitype BBA 12287 = BBA 63627 = CBS 219.76 = DAOM 225142 = IMI 202876 = NRRL 13613).

Description & Illustrations — See Nirenberg (1976), Gerlach & Nirenberg (1982).

Notes — This taxon was first described as a species of Fusisporium by Schröter in 1874 and then as a species of Fusarium in 1892 by Saccardo. Although Wollenweber & Reinking (1935) considered this species as a synonym of F. anthophilum (as F. moniliforme var. anthophilum), both Nirenberg (1976) and Gerlach & Nirenberg (1982) recognised this species, indicating CBS 219.76 (= NRRL 13613 = IMI 202876) as a representative isolate of F. succisae. Therefore, this specimen is designated as epitype for this species.

Fusarium verticillioides (Sacc.) Nirenberg, Mitt. Biol. Bundesanst. Land-Forstw. 169: 26. 1976 — Fig. 12, ​,1313

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Fig. 12

Lectotype of Fusarium verticillioides (Saccardo 1881).

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Fig. 13

Fusarium verticillioides (CBS 218.76^ET). a. Colonies in PDA after 7 d at 25 °C light, dark and nuv (from left to right), respectively; b. aerial conidia produced in chains; c. aerial conidia; d–e. aerial conidia, conidiophores and phialides. — Scale bars: c–g = 10 μm.

Basionym. Oospora verticillioides Sacc., Fung. Ital., Fasc. 17–28: pl. 879. 1881.

Synonyms. Alysidium verticillioides (Sacc.) Kuntze, Revis. Gen. Pl. 3: 442. 1898.

Fusarium moniliforme J. Sheld., Annual Rep. Nebraska Agric. Exp. Sta. 17: 23. 1904.

Gibberella moniliformis Wineland, J. Agric. Res. 28: 909. 1924.

Typus. ITALY, Zea mays, 1877, unknown collector (lectotype of Oospora verticillioides, MBT 10000421, pl. 879 in Saccardo, Fung. Ital. (1881), designated here); GERMANY, on stem of Zea mays, 1968, H. Nirenberg (epitype, MBT 10000422, CBS 218.76 (preserved as metabolically inactive culture), designated here, culture ex-epitype CBS 218.76 = BBA 11782 = DSM 62264 = IMI 202875 = NRRL 13993).

Description & Illustrations — See Nirenberg (1976, 1981), Gerlach & Nirenberg (1982), Leslie & Summerell (2006).

Notes — Fusarium verticillioides was first isolated from maize in Italy in 1877 as Oospora verticillioides (Saccardo 1886) and became known as F. moniliforme after it was associated with animal toxicoses (Sheldon 1904). Nirenberg (1976) synonymised O. verticillioides under F. moniliforme, associated with the sexual morph Gibberella moniliformis (Wineland 1924). Previously, the name F. moniliforme was applied in a broad sense to include at least six, and probably more, reproductively isolated mating populations. Therefore, Seifert et al. (2003) restricted the application of the name F. verticillioides to what is presently known as the mating population A and the main fumonisin producing species. Other mating populations known within the collective ‘F. moniliforme’ group have now been resolved to species level, e.g., F. thapsinum from sorghum, F. sacchari from sugar cane, F. mangiferae from mango and F. fujikuroi from rice (Leslie & Summerell 2006). No type material could be located for the true F. verticillioides as reported by Nirenberg (1976), but the original plate published in Saccardo (1881) is selected as lectotype here. Gerlach & Nirenberg (1982) considered CBS 218.76 an authentic strain of F. verticillioides. Therefore, this metabolically inactive culture is designated as an epitype for F. verticillioides.