Morphology

Cultures were incubated on oatmeal agar (OA, which favours synnema development), malt extract agar (MEA) and dichloran 18 % glycerol agar (DG18) plates (recipes from Samson et al. 2010) at 25 °C in the dark. After 14 d, growth rates were measured and colony characters noted. Colony colours were rated following the charts of Rayner (1970). Dried herbarium material was rehydrated in sterile water, which was then replaced by Shear's mounting media for photomicroscopy (Crous et al. 2009). Measurements and descriptions of microscopic structures were made from cultures grown on synthetic nutrient agar (SNA, Samson et al. 2010) at 25 °C in the dark for 14 d, mounted in 85 % lactic acid. Macroscopic photographs were made with a Nikon SMZ25 stereo microscope equipped with a Nikon DS-Ri2 high-definition colour camera head. Photomicrographs of diagnostic structures were made with a Zeiss Axio Imager A2 microscope equipped with a Nikon DS-Ri2 high-definition colour camera head, using differential interference contrast (DIC) optics and the Nikon software NIS-elements D v. 4.50.

Taxonomy

Acaulium album Seifert & Woudenb., comb. nov. MycoBank MB821421. Fig. 4, Fig. 5.

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Fig. 4

Acaulium album DAOMC 226656. A. Four weeks old colony on cornmeal agar. B. Colony surface showing white conidial columns. C. Individual synnemata in side view. D. Synnema with apical conidiophores and broader central hypha. E. Conidia. F. Individual conidiophore on side of synnema. G. Top of synnema showing divergent conidiophores. Scale bars: D. 50 μm. E–G. 10 μm.

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Fig. 5

Line drawings illustrating conidiophores and conidia of Acaulium album.

Basionym: Synpenicillium album Costantin, Bull. Soc. Mycol. Fr. 4: 62. 1888.

≡ Coremium album (Costantin) Sacc. & Traverso, Syll. fung. 22: 1444. 1913.

≡ Cephalotrichum album (Costantin) Seifert, CBS Biodiversity Series 12: 309. 2013.

Synonyms: Penicillium costantini Bainier, Bull. Soc. Mycol. Fr. 4: 67. 1888. [Non Penicillium album Preuss 1851] ≡ Scopulariopsis costantini (Bainier) Dale, Ann. Mycol. 12: 57. 1914.

Stysanus putredinis Corda, Icon. fung. (Prague) 3: 12. 1839 fide Morton & Smith 1963 ≡ Doratomyces putredinis (Corda) F.J. Morton & G. Sm., Mycol. Pap. 86: 83. 1963. Non Graphium putredinis (Corda) S. Hughes, Can. J. Bot. 36: 770. 1958 ≡ Parascedosporium putredinis (Corda) Lackner & de Hoog, IMA Fungus 2: 44. 2011.]

Acaulium fulvum Sopp, Skr. VidenskSelsk. Christiania, Kl. I, Math.-Natur., no. 11: 67. 1912 (fide Morton & Smith 1963, but synonymy rejected by Abbott (2000) because of discrepancies in spores sizes, and in the absence of a type specimen).

Conidiophores often mononematous in vitro, astipitate, or with a short stipe up to 250 μm tall, then monoverticillate, or irregularly biverticillate or terverticillate, or reduced to single conidiogenous cells; structures with similar dimensions to those in synnemata. Synnemata on the natural substrate scattered or caespitose, up to 500–700(–1 000) μm tall, stipes white, cream-coloured or eventually very pale brown, 10–45 μm wide, unbranched or with 1–3 side branches, conidial heads hyaline to white, divergent or feathery about 20–65 μm wide and tall. Hyphae of stipe hyaline, smooth walled, in two zones: an outer region of parallel hyphae 2.5–4.5 μm wide; surrounding a central broader hypha 7–11 μm wide, with individual cells (10–)20–45 μm long. Setae absent. Conidiophores in synnemata irregularly biverticillate or terverticillate, branches 16–22 × 3–4 μm, metulae 9–13 × 3–3.5 μm. Conidiogenous cells percurrent, ampulliform, hyaline, smooth-walled, 6–8.5 μm long, 2.5–3 μm broad at the widest part, with a distinct shoulder tapering to a cylindrical annellated zone 1.5–2.5 μm wide, up to 6.5 μm long, annellations inconspicuous; in terminal whorls of 3–6. Conidia obovoid, ellipsoidal to irregularly fusiform with a truncate base and rounded or bluntly pointed apex, 4.5–6.5(–7) × 2–3(–4) μm, hyaline, smooth and slightly thick-walled, in long, dry, basipetal chains, sometimes sticking laterally and forming columns up to 1 mm long. Chlamydospores abundant in culture, sometimes also in the synnema stipe, globose to ellipsoidal, 4–8 × 4–5 μm, single or in pairs, cyanophilous. Sexual morph not observed.

Culture characteristics: Colonies on OA 46–47 mm diam after 14 d at 25 °C, planar to low convex, powdery, white to cream-coloured centre with hyaline outer ring, margin discrete, undulate. On MEA 44–45 mm diam, planar to low convex, powdery, white to cream with inconspicuous concentric rings about 1 mm apart, margin undulate.

Specimens and cultures examined: Canada, British Columbia, Vancouver, University of British Columbia (UBC), near University Golf Club, from decaying Coprinus micaceus, July 1981, J. A. MacKinnon, CBS 257.82 = ATCC 46569 (DAOM 230530); British Columbia, Vancouver, UBC Campus, 22 Oct. 1980, R.J. Bandoni, CBS H-3873; Same location, UBC chicken coop, 19 Jan. 1980, on chicken droppings, R.J. Bandoni & T. Thompson, CBS H-3874. Same location, UBC Experimental Garden, 2 Feb. 1981, on rotting potato, J.A. MacKinnon, CBS H-3872. Ontario, Ottawa-Carleton Twp, Bell's Corners, 9 May 1998, on bear dung (Ursus americanus), Keith A. Seifert no. 521 (DAOM 226656). Czech Republic, Prague, on rotting stems of Echium sp., 1838, Fieber (holotype of Stysanus putredinis, PR-C 155673). Denmark, from bumble-bee queen, collection date unknown, J.P. Skou, CBS 378.64. Netherlands, Hoogland, near Amersfoort, from hair in dung of pole cat (Mustela putorius), March 1984, H.A. van der Aa, (epitype designated here CBS H-12128, MBT376922, culture ex-epitype CBS 539.85); Wageningen, from soil, collection date unknown, J.H. van Emden, CBS 212.73. USA, Maine, Kittery Point, from decaying seaweed, 1918, R. Thaxter (FH).

Notes: De Beer et al. (2013, p. 309) briefly reviewed the history of the epithet ‘putredinis’ and its contradictory use in Graphium and Doratomyces, which need not be repeated in detail here. Because the epithet putredinus is now used in Parascedosporium but previously was being used for two distinct species (one by Hughes 1958, the other by Morton & Smith 1963), it was necessary to transfer the next available epithet, i.e. from Synpenicillium album, to Cephalotrichum. The recent treatment by Sandoval-Denis et al. (2016b) noted morphological similarities between this species (as C. album) and other asexual species included in the Acaulium clade by molecular evidence, but did not redescribe or reclassify this white species. The phylogenetic analysis presented here (Fig. 3) shows that this species does not belong to Cephalotrichum, and is best classified as a synnematous species of Acaulium as suggested by Sandoval-Denis et al. (2016b).

 Acaulium album is a relatively infrequently reported asexual fungus, but is broadly distributed in Europe and North America on heavily decayed organic material and various kinds of (often carnivore) dung. Apart from the white synnemata and spores, it is distinctive because of the broad hypha in the centre of the synnema stipe. Developmentally, the synnemata are rather odd. The cells of the broad central hypha produce narrower hyphae growing upward near the top of the cells or hyphae growing downward from the bottom of the same cells, all appressed to the central cylinder to make up the stipe. The downward growing hyphae anchor the conidiomata to the substrate; the upward growing hyphae branch to become the conidiophores. Similar downward growing hyphae, and broader core hyphae, are sometimes seen in the synnema stipes of true Cephalotrichum species (Lodha, 1963, Swart, 1964) but are more difficult to see because of the pigmentation of the cells.

 Costantin (1888) described his fungus from panther dung from an unreported location, but probably from a zoo in Paris. Morton & Smith (1963) did not locate a type, but considered the identity of the fungus clear from the published illustration. There is a discrepancy in spore sizes, Costantin (1888) reporting dimensions of 7–13 × 3–6 μm, roughly double the size reported here, but given our observations of several specimens of the relatively common species described above, suspect this is probably a measurement error by Costantin (1888). We designate CBS H-12128, isolated from a hair in pole cat dung, as epitype above to further stabilise the species name.

 Synpenicillium is an older name than Acaulium but has rarely been used after its original publication in 1888 (Costantin). Acaulium has generally been considered a synonym of Scopulariopsis but recently was re-instated as an accepted genus of Microascaceae with three species (Sandoval-Denis et al. 2016b). Although both names are relatively obscure, we see no reason to resurrect Synpenicillium for this clade. We will propose protection of Acaulium be added to the list of protected generic names now being discussed by the nomenclatural community.

Cephalotrichum domesticum Woudenb. & Seifert sp. nov. MycoBank MB819314. Fig. 6.

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Fig. 6

Cephalotrichum domesticum sp. nov. CBS 142035. A–C. Fourteen day old colonies on OA (A), MEA (B) and DG18 (C). D–G. Synnemata. H–I. Conidiophores, conidiogenous cells and conidia. J. Conidia. Scale bars = 10 μm.

Etymology: The name refers to the usual occurrence of this species in the built environment, or other environments manipulated by humans, such as farms.

Mononematous conidiophores abundant among and intergrading with synnemata, hyaline to pale brown, monoverticillate, or irregularly biverticillate to terverticillate, sometimes 3–4- level verticillate, with a short stipe 7–25 μm tall, terminating in 3–5(–7) annellides on cylindrical, clavate or swollen metulae 5–8 × 2.5–3.5 μm; branches appressed or divergent, 10–12 × 2–3 μm. Synnemata 130–225(–245) μm tall, stipes pale brown, 7–10 μm wide, composed of rather loosely attached hyphae; conidial heads brown, subglobose to ellipsoidal. Hyphae of stipe parallel, 2–4 μm wide, pale-brown, slightly thick-walled. Setae absent. Conidiophores in synnemata monoverticillate, irregularly biverticillate or conidiogenous cells arising directly from the stipe hyphae, with all elements tightly appressed, metulae 5.5–8.5 × 2–2.5 μm. Conidiogenous cells ampulliform, (5.5–)6–7.5(–8) μm long, 2.5–3(–3.5) μm broad at the widest part, tapering gradually to a cylindrical annellate zone 1.5–2 μm wide, hyaline to pale brown, smooth-walled. Conidia ellipsoidal to cylindrical with truncate base and rounded or pointed apex, 5.5–6(–6.5) × 3–3.5(–4) μm, pale brown to brown, smooth and thick-walled, in basipetal chains. Sexual morph not observed.

Culture characteristics: Colonies on OA 52–55 mm diam after 14 d at 25 °C, low convex, felty, white with iron grey synnemata, margin crenate. On MEA 45–50 mm diam, low convex, finely felty, white with olivaceous grey to iron grey centre, margin uneven. On DG18 13–15 mm diam, planar, finely felty, white with iron grey zones, margin undulate.

Specimens examined: Netherlands, Limburg, from manure, Mar. 1942, P.J. Bels, CBS 139.42 = IFO 7677 = MUCL 4025; Utrecht, dried culture of strain isolated from indoor air of home (kitchen), 28 Aug. 2008, J. Houbraken, (holotype CBS H-22856, culture ex-type CBS 142035); from plaster, before Sept. 1967, H.J. Hueck, CBS 395.67; from mushroom compost, 1950, H.C. Bels-Koning, CBS 255.50 = MUCL 4037.

Notes: Only the ex-type culture CBS 142035 produced synnemata in culture. This phenomenon has also been reported for C. purpureofuscum, where several colonial variants can be obtained by spontaneous sectoring (Domsch et al. 2007). Although morphologically C. domesticum resembles C. purpureofuscum, it can easily be separated from that based on any of the three genes studied here (see Discussion section notes regarding C. purpureofuscum). Given the similar morphology, frequently defined by lack of distinctive characters, examination of a larger number of isolates for C. domesticum and C. purpureofuscum is needed to adequately assess whether any consistent morphological features could be used to identify the species that are clearly distinct based on molecular data. Phylogenetically C. domesticum is closely related to C. tenuissimum. The smaller synnemata of C. domesticum (130–245 μm tall vs. 495–900 μm tall) and faster growth on OA (52–55 mm diam vs. 40 mm) and MEA (45–50 mm diam vs. 30 mm) at 25 °C can be used to distinguish the two species.

Cephalotrichum lignatile Woudenb. & Seifert sp. nov. MycoBank MB819309. Fig. 7.

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Fig. 7

Cephalotrichum lignatile sp. nov. CBS 209.63. A–C. Fourteen day old colonies on OA (A), MEA (B) and DG18 (C). D–F. Synnemata. G. Detail of the apical portion of a synnema. H–I. Conidiophores, conidiogenous cells and conidia. J. Conidia. Scale bars = 10 μm.

Etymology: The name refers to the substrate of isolation, timber.

Mononematous conidiophores moderately abundant among synnemata, pale brown, mostly monoverticillate or biverticillate with a short stipe 4–10(–14) × 2–3 μm, sometimes 2-level verticillate, with (2–)3–5 annellides in compact whorls on slightly divergent, cylindrical to slightly clavate metulae 7–8 × 1.5–2.5 μm. Synnemata (280–)300–445(–465) μm tall, stipes pale brown to brown, (5.5–)6–8.5 μm wide, unbranched, conidial heads hyaline to pale brown, ellipsoidal or cylindrical. Hyphae of stipe parallel, 2–2.5 μm wide, pale-brown, slightly thick-walled. Setae absent. Conidiophores in synnemata irregularly monoverticillate, biverticillate or 2–3(–4)-level verticillate with all elements tightly appressed, metulae 6–8 × 2–3(–3.5) μm. Conidiogenous cells ampulliform, hyaline to pale brown, smooth-walled, (5.5–)6–7(–7.5) μm long, 2.5–3 μm broad at the widest part, tapering gradually to a cylindrical annellate zone (1–)1.5(–2) μm wide, annellations inconspicuous. Conidia obovoid to irregularly fusiform with truncate base and rounded or bluntly pointed apex, (4.5–)5–6(–6.5) × (2.5–)3–3.5(–4) μm, pale brown to brown, smooth and thick-walled, in basipetal chains. Chlamydospores absent. Sexual morph not observed.

Culture characteristics: Colonies on OA 36 mm diam after 14 d at 25 °C, planar to low convex, finely felty, dull green centre with white outer ring, margin uneven. On MEA 35 mm diam, low convex, felty, white to buff with pale olivaceous grey zones, radially striate, margin undulate. On DG18 14 mm diam, low convex, finely felty, buff with rosy buff centre, radially striate, margin uneven.

Specimen examined: Belgium, Han-sur-Lesse, dried culture of strain isolated from timber in a cave, 1959, G.L. Hennebert, (holotype CBS H-22852, culture ex-type CBS 209.63).

Notes: The sequences of CBS 209.63, which we describe here as C. lignatile, are identical to the sequences previously published for CBS 159.66 as C. columnare (Sandoval-Denis et al. 2016b). However, the morphology of CBS 209.63 does not match CBS 159.66. We also sequenced older batches of CBS 159.66 from the CBS collection to exclude the possibility of a mix-up, but all gave identical sequence results, placing C. columnare in the genus Kernia, where it is transferred below. The sequences associated with this strain by Sandoval-Denis et al. (2016b) seem to contain an error that we can't explain.

Cephalotrichum telluricum Woudenb. & Seifert sp. nov. MycoBank MB819318. Fig. 8.

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Fig. 8

Cephalotrichum telluricum sp. nov. CBS 336.32. A–C. Fourteen day old colonies on OA (A), MEA (B) and DG18 (C). D–H, J. Synnemata. I. Detail of the apical portion of a synnema. K. Conidiophores, Conidiogenous cells and conidia. L. Conidia. Scale bars = 10 μm.

Etymology: The name refers to the substrate of isolation, soil.

Mononematous conidiophores sparse among synnemata, hyaline, unbranched to monoverticillate or irregularly biverticillate, bearing 1–3 annellides on cylindrical or swollen metulae 7–12 × 2.5–3 μm. Synnemata 260–424(–490) μm tall, stipes pale brown to brown, 8.5–11.5(–12.5) μm wide, conidial heads pale brown to brown, subglobose or ellipsoidal. Hyphae of stipe parallel, 2–4 μm wide, pale-brown, slightly thick-walled, wider hyphae in the centre of the stipe near the base, downward growing branches occurring near the base of the synnemata. Setae coiled, simple, septate, pale brown, individually up to about 180 μm long, 3–4.5 μm wide, extending about 70–100 μm beyond the level of the conidiogenous cells with a rounded or acute apex. Conidiophores in synnemata solitary and lateral on stipe hyphae, or monoverticillate, metulae 6–8 × 2–3 μm. Conidiogenous cells ampulliform, (5.5–)6.5–8(–8.5) μm long, 2.5–3.5(–4) μm broad at the widest part, tapering gradually to a cylindrical annellate zone (1–)1.5–2 μm wide, hyaline, smooth-walled. Conidia ovoid to broad fusiform with truncate base, (5.5–)6–7.5(–8) × (3.5–)4–4.5 μm, pale brown, smooth, thick-walled, in basipetal chains. Sexual morph not observed.

Culture characteristics: Colonies on OA 65 mm diam after 14 d at 25 °C, planar, finely felty with tufts of mycelium, grey olivaceous with pale greenish grey mycelium and (pale) olivaceous grey sectors in the centre and a white outer ring, margin entire. On MEA 60–62 mm diam, planar to low convex, floccose, white with pale greenish grey ring and lavender grey to smoke grey regions, margin entire. On DG18 10–12 mm diam, raised, finely felty, cinnamon with olivaceous grey zones and white outer ring, margin undulate.

Specimens examined: Canada, Ontario, Vineland, from soil, Sep. 1949, R.F. Cain, CBS 568.50 = TRTC 12269. Cyprus, Nicosia, dried culture of strain isolated from soil, before Jan. 1932, R.M. Nattrass (holotype CBS H-22853, culture ex-type CBS 336.32 = MUCL 9829 = UAMH 8882).

Notes: Based on morphology and phylogeny, C. telluricum is closely related to C. gorgonifer. Both species have spirally coiled setae, but the synnemata of C. telluricum (<500 μm tall) are shorter than those of C. gorgonifer (500–1 000 μm). Based on sequence data C. telluricum can be distinguished from C. gorgonifer by all three genes, with ITS having 5 nt differences, tub2 15 nt, and tef1 3 nt between C. telluricum and the ex-epitype isolate of C. gorgonifer, CBS 635.78.

Cephalotrichum tenuissimum Woudenb. & Seifert sp. nov. MycoBank MB819317. Fig. 9.

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Fig. 9

Cephalotrichum tenuissimum sp. nov. CBS 127792. A–C. Fourteen day old colonies on OA (A), MEA (B) and DG18 (C). D–G. Synnemata. H. Detail of the apical portion of a synnema. I–J. Conidiophores, conidiogenous cells and conidia. K. Conidia. Scale bars = 10 μm.

Etymology: The name refers to the slender synnemata.

Mononematous conidiophores fairly frequent among synnemata, biverticillate to terverticillate but often irregular, bearing 3–5 annellides on cylindrical or swollen metulae 5–8.5 × 2–3 μm; branches divergent, 7.5–12.5 × 2–3 μm; stipe 5–20(–70) × 2–3 μm. Synnemata (495–)630–895(–900) μm tall, stipes pale brown to brown, (14–)15–21(–24.5) μm wide, conidial heads pale brown, obclavate. Hyphae of stipe parallel, brown, 1.5–2.5 μm wide. Setae absent. Conidiogenous cells ampulliform, (5–)6–8(–8.5) μm long, 2.5–3.5 μm broad at the widest part, tapering gradually to a cylindrical annellated zone 1–1.5(–2) μm wide, hyaline, smooth-walled, usually singly and arising at +/− right angles from hyphae of the stipe, sometimes in groups of 2–3 on short metulae. Conidia ellipsoidal with truncate base and rounded apex, (4.5–)5–6(–6.5) × (3–)3.5–4 μm, hyaline to pale green-brown, smooth, thick-walled, single or in short chains. Sexual morph not observed.

Culture characteristics: Colonies on OA 40 mm diam after 14 d at 25 °C, planar, felty, colourless with olivaceous grey synnemata, margin uneven. On MEA 30 mm diam, low convex to umbonate, felty, olivaceous grey with thin pale olivaceous grey ring, radially striate, margin crenated. On DG18 15 mm diam, crateriform, pale olivaceous grey with buff edge, radially striate, margin uneven.

Specimen examined: USA, Wyoming, Hanna, dried culture of strain isolated from soil, 1976, M. Christensen (holotype CBS H-22855, culture ex-type CBS 127792 = RMF H 318).

Notes: Based our phylogenies, C. tenuissimum is closely related to C. domesticum and C. dendrocephalum. Morphologically it is easily distinguished from C. domesticum (see notes under C. domesticum) and C. dendrocephalum, which forms characteristic, undulating, branched setae. The ex-type isolate of C. tenuissimum (CBS 127792) was originally identified in CBS as C. microsporum. However, C. tenuissimum can be distinguished from C. microsporum by the size of the conidia, 5–6 × 3.5–4 for C. tenuissimum vs. 3.5–5 × 2–3 μm for C. microsporum.

Cephalotrichum transvaalense Woudenb. & Seifert sp. nov. MycoBank MB819312. Fig. 10.

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Fig. 10

Cephalotrichum transvaalense sp. nov. CBS 448.51. A–C. Fourteen day old colonies on OA (A), MEA (B) and DG18 (C). D–H. Synnemata. I. Detail of synnema setae. J. conidiophores, conidiogenous cells and conidia K. Conidia. Scale bars = 10 μm.

Etymology: The name refers to the Transvaal Province in South Africa, where the ex-type strain was first isolated.

Mononematous conidiophores monoverticillate to irregularly biverticillate, or 2–3-level verticillate. Synnemata 500–1 500 μm tall, stipes brown, 15–35 μm wide, unbranched, conidial heads pale brown to brown, ellipsoidal; sessile conidiomata lacking a stipe present in some transfers, forming brown to black, subglobose conidial tufts. Hyphae of stipe parallel, 2–4 μm wide, pale-brown, slightly thick-walled. Setae straight, aseptate, brown, (40–)70–110 μm long, 1–1.5 μm wide, base sometimes swollen to 2–2.5 μm wide, unbranched, bifurcate (90–120°) or with several layers of basal branching; sometimes arising from the same hyphae or metulae as conidiogenous cells. Conidiophores in synnemata mostly biverticillate, sometimes monoverticillate, metulae divergent, 5–8 × 2–3 μm. Conidiogenous cells ampulliform, 6–8(–10) μm long, 2–3 μm broad at the widest part, tapering abruptly to a cylindrical annellate zone 1–1.5 μm wide, pale brown, smooth-walled. Conidia ovoid to ellipsoidal with small truncate base and rounded apex, (4.5–)5–6.5 × 3–4.5 μm, pale brown, smooth, thick-walled, in basipetal chains. Sexual morph not observed.

Culture characteristics: Colonies on OA 53 mm diam after 14 d at 25 °C, planar, felty, white with olivaceous grey ring and pale olivaceous grey centre, margin uneven. On MEA 48 mm diam, low convex, wooly, white to (pale) olivaceous grey, margin entire. On DG18 15 mm diam, crateriform, planar, olivaceous grey with white to pale olivaceous grey centre, radially striate, margin entire.

Specimen examined: South Africa, Transvaal, dried culture of strain isolated from Eucalyptus saligna timber in cellar, 1951, leg. Bekker (holotype CBS H-22854, culture ex-type CBS 448.51 = IFO 7660 = IMI 046251 = LSH BB344 = UAMH 8848).

Notes: With the straight setae arising from the conidial head, C. transvaalense morphologically resembles C. cylindricum and the holotype strain was identified as this species in the past. IMI 46251 was used as the basis for the description of C. cylindricum (as Trichurus terrophilus) by Lodha (1963) and Swart (1964); their illustrations and descriptions indicate well-developed synnemata and some aspects of our description are adapted from these sources. Because the strain no longer makes well-developed synnemata, we have adapted measurements and details from these descriptions in our technical description above. Cephalotrichum transvaalense and C. cylindricum are closely related but distinct based on molecular data. The ITS sequences have no differences, but 20 nt differences in tub2 and 9 nt differences in tef1 sequences clearly distinguish the two species.

Kernia columnaris (H.J. Swart) Woudenb. & Samson comb. nov. MycoBank MB820690.

Basionym: Doratomyces columnaris H.J. Swart, Acta Bot. neerl. 15: 521. 1967 ≡ Cephalotrichum columnare (H.J. Swart) S.P. Abbott, Stud. Mycol. 83:206. 2016.

Descriptions and illustrations: Swart, 1967, Abbott, 2000, Sandoval-Denis et al., 2016a, Sandoval-Denis et al., 2016b.

Specimen examined: South Africa, Johannesburg, Melville Koppies Nature Reserve, from dung of hare, 1964, H.J. Swart (culture ex-type CBS 159.66 = IMI 116691).

Notes: As noted, sequences previously published for CBS 159.66 (Sandoval-Denis et al. 2016b) match sequences of CBS 209.63, which we describe above as C. lignatile. To exclude the possibility of mislabelling in the CBS collection, we also studied older preservation batches of CBS 159.66 from the CBS collection, which all yielded identical sequence results that convincingly place this species in the genus Kernia (Fig. 3). The affinity of this species with the latter genus rather than Cephalotrichum was already suggested by Abbott (2000), based on significantly discordant morphological characters recorded from several isolates, including its reduced conidiophores (50–700 μm), mostly mononematous or more rarely synnematous with poorly developed, hyaline stipes, which resemble more to those of the synnematous anamorphs of Kernia hippocrepida and K. pachypleura (Malloch & Cain 1971). Other relevant features of K. columnaris are: annellides subcylindrical to ampulliform, conidia ellipsoid, often slightly asymmetrical, apex rounded or bluntly pointed, smooth, 5–6 × 2.5–4 μm, commonly 5.5 × 3 μm, colonies grey to brown, slow growing (20–30 mm in 14 d at 25 °C). The mentioned characteristics match with the morphological treatment of the species by Sandoval-Denis et al., 2016a, Sandoval-Denis et al., 2016b, suggesting that their illustrations are based on the actual ex-type strain of K. columnaris, while the sequence discrepancy most likely respond to a sequencing overlap.

Doubtful and excluded species

Cephalotrichum acutisporum J.J Xu & T.Y. Zhang, Mycotaxon 117: 208. 2011.

Specimen examined: China, Fujian Province, Zhangping, dried culture isolated from soil of a park, Oct. 22. 2004, J.J. Xu (holotype HSAUPII₀₄2724 → isotype CBS H-22780, additional isotype HMAS196222).

Notes: This species is a synonym of C. purpureofuscum. Synnemata and conidiogenous cells in the isotype material are much larger than indicated in the protologue. According to our observations synnemata are (600–)640–955 μm tall, with conidiogenous cells (8.5–)9.5–10.5 × (2.5–)3–4 μm. Also, the conidial shape, originally described and illustrated as markedly pointed is not a consistent character; nearly half of the conidia observed in the isotype have rounded apices, a pattern commonly observed in C. purpureofuscum.

Cephalotrichum cylindrosporum Y.L. Zhang & T.Y. Zhang, Mycotaxon 117: 209. 2011.

Specimen examined: China, Hainan Province, Tunchang, dried culture isolated from rice field soil, Nov. 1. 2005, Y.L. Jiang (holotype HSAUPII₀₅2414 → isotype CBS H-22782, additional isotype HMAS196223).

Notes: The fungus on the isotype is morphologically indistinguishable from C. purpureofuscum. As noted by Sandoval-Denis et al. (2016b), this is a serious discrepancy from the ITS sequence derived from the ex-type (FJ914686), which matches the epitype of C. stemonitis, and hence cannot represent C. purpureofuscum (Fig. 2). It is probable that mislabelling or cross contamination of the original culture occurred, and the name must be regarded as a nomen dubium.

Cephalotrichum inflatum Y.L. Jiang & T.Y. Zhang, Mycotaxon 117: 213. 2011.

Specimen examined: China, Sichuan Province, Mianyang, dried culture isolated from mountain soil, Aug. 8. 2005, Y.L. Jiang (holotype HSAUPII₀₅0918 → isotype CBS H-22784, additional isotype HMAS196226).

Notes: This species is a synonym of C. microsporum. The main distinctive feature of C. inflatum was the presence of distinctly swollen cells at the top of the synnemata, from which the conidiogenous cells arise. When cultures were grown on PDA, this feature was also observed in our C. microsporum isolates. Although the ITS sequence of C. inflatum has 1 nt difference from the ex-type strain of C. microsporum (CBS 523.63), it is identical to that of C. microsporum strain DTO 207-C6.

Cephalotrichum longicollum Y.L. Jiang & T.Y. Zhang, Mycotaxon 117: 213. 2011.

Specimen examined: China, Sichuan Province, Emei Mountain, dried culture isolated from soil, Aug. 9. 2005, Y.L. Jiang (holotype HSAUPII₀₅0802 → isotype CBS H-22785, additional isotype HMAS196228).

Notes: This species is a synonym of C. purpureofuscum. The original description is inaccurate, according to our observations, with conidiogenous cells 8–11(–12.5) × (2.5–)3–4 μm, and conidia (4–)5–6 × 3–3.5(–4) μm. The isotype material contains only short synnemata 475–500 μm tall; however, synnemata of this stature are not uncommon in C. purpureofuscum. Morton & Smith (1963) examined isolates of C. purpureofuscum with reduced synnemata, as little as 50 μm tall. The morphological identity with C. purpureofuscum is confirmed by DNA data. The ITS sequence from the ex-type of C. longicollum has 1 nt difference from the reference strain of C. purpureofuscum (CBS 174.68, Fig. 2), but is identical to the ITS sequences of the other C. purpureofuscum isolates included in this study (data not shown).

Cephalotrichum macrosporum Y.L. Jiang & T.Y. Zhang, Mycotaxon 117: 214. 2011.

Specimen examined: China, Sichuan Province, Jiuzhaigou, dried culture isolated from forest soil, Aug. 18. 2005, Y.L. Jiang (holotype HSAUPII₀₅0878 → isotype CBS H-22786, additional isotype HMAS196229).

Notes: The isotype is in poor condition. Only fragments of synnema stipes and conidia can be seen, and the fungus is unidentifiable. The conidial dimensions, (4–)5.5–7.5(–10) × (2.5–)3.5–4(–4.5) μm, and unusual conidial shapes, cylindrical, irregularly cylindrical, curved or cashew-nut shaped, reflect the degraded state of the material. The ITS sequence from the ex-type has 1 nt difference with the reference strain of C. purpureofuscum (CBS 174.68, Fig. 2), but is identical to the ITS sequences of the other C. purpureofuscum isolates included in this study (data not shown). Provisionally, C. macrosporum seems to be a synonym of C. purpureofuscum. Fresh isolations of this fungus may clarify this status, or the remainder of the holotype will need to be examined to observe undamaged synnemata.

Cephalotrichum oblongum J.J. Xu & T.Y. Zhang, Mycotaxon 117: 216. 2011.

Specimen examined: China, Yunnan Province, Pingbian County, dried culture isolated from soil, Oct. 11. 2004, J.J. Xu (holotype HSAUPII₀₄2723 → isotype CBS H-22787, additional isotype HMAS196230).

Notes: This is a synonym of C. purpureofuscum. The isotype material contains elements of two fungi, synnemata of C. purpureofuscum and numerous mesoconidia and macroconidia of a Fusarium spp. The original description deviates from our observations of the synnemata on the type material. Synnemata are taller than reported, (305–)325–650 μm tall, the conidiogenous cells are shorter and wider, 5.5–8 × 3–4 μm, and the conidia are larger, (4.5–)5–6(–6.5) × (2.5–)3–3.5(–4) μm, all dimensions that fit well with C. purpureofuscum. The ITS sequence has 1 nt difference from the reference strain of C. purpureofuscum (CBS 174.68, Fig. 2), but is identical to the ITS sequences of the other C. purpureofuscum isolates included in this study (data not shown).

Cephalotrichum ovoideum Y.L. Jiang & T.Y. Zhang, Mycotaxon 117: 217. 2011.

Specimen examined: China, Sichuan Province, Jiuzhaigou, dried culture isolated from forest soil, Aug. 18. 2005, Y.L. Jiang (holotype HSAUPII₀₅0846 → isotype CBS H-22788, additional isotype HMAS196231).

Notes: Based on the original publication, this species could be synonymised with C. microsporum. However, the isotype material is in poor condition. Only conidia were observed, while synnema stipes and conidial heads were not well preserved. The ITS phylogeny suggests a close affinity with both C. microsporum and C. robustum. Until the remainder of the holotype can be examined, or a fresh isolate obtained, C. ovoideum should be considered a provisional synonym of C. microsporum.

Cephalotrichum robustum Y.L. Jiang & T.Y. Zhang, Mycotaxon 117: 218. 2011.

Specimen examined: China, Sichuan Province, Jiuzhaigou, dried culture isolated from forest soil, Aug. 18. 2005, Y.L. Jiang (holotype HSAUPII₀₅0875 → isotype CBS H-22789, additional isotype HMAS196232).

Notes: This fungus morphologically resembles C. microsporum, C. purpureofuscum and C. ovoideum, but conclusive comparisons are impossible because of the poor condition of the isotype material (see notes on C. ovoideum above). The ITS phylogeny shows a relationship with C. microsporum, from which C. robustum differs morphologically by its shorter synnemata and longer conidia. This species is provisionally synonymised with C. microsporum until the holotype material of fresh isolations can be examined.

Cephalotrichum terricola Y.L. Jiang & T.Y. Zhang, Mycotaxon 117: 221. 2011.

Specimen examined: China, Sichuan Province, Panzhihua, dried culture isolated from mountain soil, Aug. 13. 2005, Y.L. Jiang (holotype HSAUPII₀₅0924 → isotype CBS H-22791, additional isotype HMAS196227).

Notes: This is a synonym of C. purpureofuscum. The isotype contains two fungi, synnemata of Cephalotrichum and second hyaline fungus, probably an Aspergillus sp. The synnemata show some differences from the original description. The conidial surface is not smooth as reported but presents some fine roughness. Most conidia are finely pointed, but conidia with rounded apices were also commonly observed. The synonymy is supported by sequence data. The ITS sequence from the ex-type of C. terricola has 1 nt difference with the reference strain of C. purpureofuscum (CBS 174.68), but is identical to ITS sequences of other C. purpureofuscum isolates included in this study (data not shown).

Cephalotrichum verrucipes Y.L. Jiang & T.Y. Zhang, Mycotaxon 117: 223. 2011.

Specimen examined: China, Sichuan Province, Jiuzhaigou, dried culture isolated from forest soil, Aug. 19. 2005, Y.L. Jiang (holotype HSAUPII₀₅0849 → isotype CBS H-22792, additional isotype HMAS196234).

Note: This is a synnematous Penicillium species closely matching morphologically with P. clavigerum. Apart from the reported percurrent rather than phialidic conidiogenesis, the protologue of C. verrucipes is more or less consistent with this synonymy.