NORWAY. Oslo (county): Oslo (municipality), Bygdøy, Hengsåsen, boreonemoral mixed forest on soil with high pH, 22 September 2010, S. Svantesson (holotype: O F110312!, GenBank Acc. No. ITS: MK290731).

SH032598.07FU

The name refers to the spores, which are abundantly lobed.

Basidiomata annual, resupinate, membranaceous, effused to several tens of centimetres in diameter. Mature parts continuous, with a rather firm, fibrous and compact, yet quite soft and elastic texture. Hymenium smooth, but sometimes strongly undulating; brown with a pinkish hue. Immature parts discontinuous, byssoid, with a cottony texture. Subhymenium and hymenium of immature parts blue grey to brown grey. Subiculum well developed, loose, fibrous, orange brown; often forms the outer edge of basidiomata, extending noticeably beyond the hymenium. All characters recorded in dried state.

Figure 7. 

Micromorphological features of P. abundiloba in KOH. A, B basidiospores in frontal face (TU 110852) C in tilted frontal face (TU 110852) D, E in lateral face (TU 110852) F subicular hyphae (holotype).

Hyphal cords lacking, but loose bundles of subicular hyphae sometimes present.

Hyphal system monomitic; clamp connections and reaction in Melzer’s reagent absent from all hyphae.

Subicular hyphae noticeably long and straight, thick-walled; forming a loose tissue. Individual hyphae (4.3–) 4.8–6.9 (–7.2) μm wide, with a mean width of 5.5–6.1 μm; orange brown to dark brown in both KOH and water.

Subhymenial hyphae often somewhat sinuous, thin to thick-walled; forming a rather dense tissue. Individual hyphae (4.0–) 4.1–6.8 (–7.2) μm wide, with a mean width of 5.5–5.7 μm; in the upper parts, hyaline to orange brown or orange green in KOH, with a blue green reaction in the presence of air; in the lower parts, pale orange brown to orange brown in KOH, unchanged in air; in water with strongly granular contents, orange green.

Encrustation granular, inamyloid; hyaline to orange brown or orange green in KOH, blue green in the presence of air; orange green in water; common to rare, usually scattered in occurrence on the upper parts of subhymenial hyphae and on the lower parts of basidia.

Basidia with four slightly curved sterigmata, occasionally two-sterigmate; clavate to narrowly clavate, sometimes clavopedunculate, thin-walled, with one-three slight constrictions. Dimensions: (63–) 64–92 (–93) × (8.7–) 10.0–14.4 (14.9) μm; mean dimensions: 70–81 × 11.0–12.0 μm. Sterigmata (8.4–) 9.0–12.9 (–13) μm long, with a mean length of 10.0–11.5 μm. Colours and reactions the same as for the upper parts of the subhymenial hyphae, but in addition often with granular contents in KOH.

Cystidial organs lacking.

Basidiospores in frontal face generally with a subcircular basic shape and a star-shaped, angular, nodulose or sometimes cross-shaped outline, covered in bi- or trifurcate, sometimes singularly attached, echinuli. Nearly all spores with four-seven, low but distinct, rounded to square lobes or corners; unlobed, broadly ovoid spores and rounded, heart-shaped spores infrequently occurring, as well as abnormally large spores originating from two-sterigmate basidia. Frontal dimensions: (8.8–) 9.2–10.5 × (8.0–) 8.6–10.7 (–10.8) μm; mean dimensions: 9.8 × 9.5–9.6 μm; Q-value: 0.9–1.2; mean Q-value: 1.0. Echinuli (0.9–) 1.1–1.8 (–1.9) μm long, with a mean length of 1.2–1.5 μm. Lateral face ellipsoid to semicircular, usually with evenly rounded edges, sometimes with one-three lobes. Lateral dimensions: (8.9–) 9.3–10.1 (–10.5) × (6.7–) 7.0–8.1 (–8.2) μm; mean dimensions: 9.7–9.8 × 7.3–7.7 μm; Q-value: 1.2–1.4 (–1.5); mean Q-value: 1.3. Colour in KOH pale orange green to orange brown, in the presence of air sometimes with a blue green reaction; in water pale orange green; inamyloid.

Chlamydospores lacking.

The type collection was obtained in an old, mixed forest on soil with high pH. No additional sequences are available in UNITE.

Basidiomata encountered in: Estonia and Norway.

Within the P. tristis group, the basidiomata of P. abundiloba are recognised by their lack of hyphal cords and skeletal hyphae and their soft, yet rather firm and compact and ± elastic texture after drying, bluish to greenish colour of immature parts, wide subicular hyphae, long, abundantly lobed spores and inamyloid encrustation on subhymenial hyphae and basidia. Pseudotomentella abundiloba, P. pluriloba and P. media can appear similar, but none of them has abundantly lobed spores. Pseudotomentella media further differs by having smaller spores and narrower subicular hyphae, while P. pluriloba has narrower subicular hyphae, longer sterigmata and frontally wider spores and P. alobata has amyloid encrustation on its subhymenial hyphae and basidia.

ESTONIA. Lääne: Ridala, between Uneste and Võnnu, Ehmja-Turvalepa Special Conservation Area, nutrient-rich, boreonemoral forest, 25 September 2012, L. Tedersoo (TU 110852*).

NORWAY. Buskerud: Ringerike, Juveren N, boreonemoral Alnus incana forest on soil with intermediate pH, 25 September 2010, S. Svantesson and N. Svensson (holotype: O F110313!, GenBank Acc. No. ITS: MK290715).

SH218588.07FU

The name refers to the ectomycorrhizal association of the species, which always seems to be with Alnus.

Basidiomata annual, resupinate, membranaceous, effused. Mature parts continuous, with a soft cottony texture. Hymenium smooth; blue grey, sometimes with a slightly brown hue. Immature parts discontinuous, byssoid, with a soft cottony texture. Subhymenium and hymenium of immature parts pale blue grey to blue grey. Subiculum thin to well developed, loose, fibrous, orange brown; often forms the outer edge of basidiomata, extending noticeably beyond the hymenium. All characters recorded in dried state.

Figure 8. 

Micromorphological features of P. alnophila in KOH. Holotype: A, B, C basidiospores in frontal face D, E in lateral face E subicular hyphae.

Hyphal cords lacking, but loose bundles of subicular hyphae sometimes present.

Hyphal system monomitic, clamp connections and reaction in Melzer’s reagent absent from all hyphae.

Subicular hyphae noticeably long and straight, thick-walled; forming a loose tissue. Individual hyphae 4.0–5.0 (–5.1) μm wide, with a mean width of 4.5 μm; orange brown to dark brown in KOH and orange to orange brown in water.

Subhymenial hyphae often somewhat sinuous, thin to thick-walled; forming a rather dense tissue. Individual hyphae (3.2–) 3.4–5 (–5.6) μm wide, with a mean width of 4.1 μm; hyaline to pale orange brown in KOH, blue green in the presence of air; pale green in water, with strongly granular contents.

Encrustation not seen.

Basidia with four slightly curved sterigmata, occasionally two-sterigmate; clavate to narrowly clavate, sometimes clavopedunculate, thin-walled, with one-three slight constrictions. Dimensions: (66–) 67–93 (–100) × (11.2–) 11.3–14.2 (–15.0) μm; mean dimensions: 83 × 12.8 μm. Sterigmata (9.5–) 11–14.5 (–14.8) μm long, with a mean length of 8.6 μm. Colours and reactions the same as for the subhymenial hyphae, but in addition often with granular contents in KOH.

Cystidial organs lacking.

Basidiospores in frontal face generally with a subcircular basic shape and an angular to nodulose or sometimes cross-shaped outline, covered in bi- or trifurcate, sometimes singularly attached, echinuli. Nearly all spores with three-five distinct corners or rounded to square lobes; broadly ovoid spores and rounded, heart-shaped spores infrequently occurring, as well as abnormally large spores originating from two-sterigmate basidia. Frontal dimensions: (8.8–) 9.0–10.1 (–10.4) × 9.2–10.2 (–10.6) μm; mean dimensions: 9.5 × 9.8 μm; Q-value: 0.9–1.0; mean Q-value: 1.0. Echinuli (0.8–) 0.9–1.7 μm long, with a mean length of 1.2 μm. Lateral face ellipsoid to ovoid, usually with evenly rounded edges, sometimes with one-three lobes. Lateral dimensions: 9.0–10.6 × (6.6–) 6.9–8.1 (–8.2) μm; mean dimensions: 9.6 × 7.7 μm; Q-value: 1.2–1.3 (–1.4); mean Q-value: 1.3. Colour in KOH pale orange brown to pale orange green, in the presence of air occasionally with a blue green reaction; in water pale green to pale orange green; inamyloid.

Chlamydospores lacking.

The only specimens recorded to date of P. alnophila is the type collection and one other collection from the same locality, which is a mature and, at the collection site pure, stand of Alnus incana on clay soil with intermediate pH. In addition, UNITE sequence metadata show that the species forms ectomycorrhiza with at least Alnus mandschurica (Kõljalg et al. 2005, Nilsson et al. 2019).

Basidiomata encountered in: Norway. Soil or root tip samples confirm presence also in: China.

Within the P. tristis group, the basidiomata of P. alnophila can be recognised by their lack of hyphal cords and skeletal hyphae and their soft cottony texture after drying, bluish to greenish colour of immature parts, narrow hyphae, long spores, bluish-grey mature hymenium (sometimes with a slightly brown hue) and their association with Alnus. Pseudotomentella pluriloba, P. media and P. pinophila are similar, but they all have basidiomata that are compact and rather firm after drying and whose mature parts are some shade of brown, without any bluish hue. Pseudotomentella pluriloba also has slightly longer spores and echinuli and wider subicular hyphae, while P. media and P. pinophila have generally slightly smaller microcharacters. Pseudotomentella pinophila also has a different spore shape. In addition, neither of these species has been recorded as being associated with Alnus.

NORWAY. Buskerud: Ringerike, Juveren N, boreonemoral, Alnus incana forest on soil with intermediate pH, 25 September 2010, S. Svantesson and N. Svensson (O F110314).

SWEDEN. Dalsland, Mellerud, Skållerud, Norgekullen SW, coniferous forest on soil with high pH, 20 September 2017, S. Svantesson 425 (holotype: GB!, GenBank Acc. No. ITS: MK290696).

SH030577.07FU

The name refers to the spores, which commonly lack lobation.

Basidiomata annual, resupinate, membranaceous, effused – often to several tens of centimetres in diameter. Mature parts continuous, with a cottony texture when fresh and a rather firm, fibrous and compact, yet quite soft and elastic texture when dried. Hymenium smooth, but sometimes strongly undulating; brown, purplish-brown or blue-greyish-brown when fresh, brown with a pinkish hue when dried. Immature parts discontinuous, byssoid, with a cottony texture both when fresh and when dried. Subhymenium and hymenium of immature parts blue to blue grey when fresh and blue grey to brown grey when dried. Subiculum well developed, loose, fibrous, orange brown; often forms the outer edge of basidiomata, extending noticeably beyond the hymenium.

Figure 9. 

Morphological features of P. alobata, mounted in KOH and macroscopically. A, B basidiospores in frontal face (O F110315) C, D in lateral face (O F110316) E subicular hyphae (TU 115626) F mature basidiome (holotype).

Hyphal cords lacking, but loose bundles of subicular hyphae sometimes present.

Hyphal system monomitic, clamp connections absent from all hyphae.

Subicular hyphae noticeably long and straight, thick-walled; forming a loose tissue. Individual hyphae (4.3–) 4.6–7.4 (–7.6) μm wide, with a mean width of 5.6–5.9 μm; orange in both KOH and water.

Subhymenial hyphae often somewhat sinuous, thin to thick-walled; forming a rather dense tissue. Individual hyphae (3.1–) 3.4–6.9 μm wide, with a mean width of 4.0–4.5 μm; hyaline to pale green in KOH, blue green in the presence of air; yellow to pale orange yellow in water, with strongly granular contents.

Encrustation granular, amyloid; purple in KOH, dark blue green in the presence of air; dark brown in water; usually common and scattered in occurrence on the upper parts of subhymenial hyphae and on the lower parts of basidia.

Basidia with four slightly curved sterigmata, occasionally two-sterigmate; clavate to narrowly clavate, sometimes clavopedunculate, thin-walled, with one-three slight constrictions. Dimensions: (63–) 64–91 (–98) × (10.2–) 10.5–14.2 (–14.3) μm; mean dimensions: 74–77 × 11.3–12.1 μm. Sterigmata 8.5–12.1 (–12.4) μm long, with a mean length of 10.0–10.3 μm. Colours and reactions the same as for the subhymenial hyphae, but in addition often with granular contents in KOH.

Cystidial organs lacking.

Basidiospores in frontal face generally with a subcircular basic shape and an unlobed or occasionally weakly pronounced, rounded, heart-shaped outline, covered in bi- or trifurcate, sometimes singularly attached, echinuli. Subcircular, three-five-lobed spores infrequently occurring, as well as abnormally large spores originating from two-sterigmate basidia. Frontal dimensions: (9.0–) 9.1–10.7 × (8.4–) 8.9–10.5 (–10.7) μm; mean dimensions: 9.7–10.1 × 9.5–9.8 μm; Q-value: (0.9–) 1.0–1.1; mean Q-value: 1.0. Echinuli 1.2–1.8 (–1.9) μm long, with a mean length of 1.4–1.7 μm. Lateral face ellipsoid, usually with evenly rounded edges, sometimes with one-three lobes. Lateral dimensions: (8.9–) 9.1–10.3 × (6.5–) 6.7–8.2 μm; mean dimensions: 9.7–9.9 × 7.1–7.4 μm; Q-value: (1.2–) 1.3–1.5; mean Q-value: 1.3–1.4. Colour in KOH pale brownish-yellow, in the presence of air often with a blue green reaction; in water pale greenish-yellow to pale orange yellow; occasionally amyloid.

Chlamydospores lacking.

Data on habitat are scarce to date, but recent Scandinavian collections have been made in old growth coniferous or mixed forests on soil with high pH.

Basidiomata encountered in: Norway, Slovenia and Sweden. No sequences originating from soil or root tip samples in UNITE.

Within the P. tristis group, the basidiomata of P. alobata are recognised by their lack of hyphal cords and skeletal hyphae and their soft, yet rather firm and compact and ± elastic texture after drying, bluish to greenish colour of immature parts, wide subicular hyphae, long, unlobed spores and amyloid encrustation on subhymenial hyphae and basidia. Pseudotomentella abundiloba, P. pluriloba and P. media can appear similar, but none of them has spores which generally are unlobed. P. media further differs by having smaller spores and narrower subicular hyphae, while P. pluriloba has narrower subicular hyphae, longer sterigmata and frontally wider spores than P. alobata. Pseudotomentella abundiloba sometimes has encrusted subhymenial hyphae and basidia, but without amyloid reaction.

NORWAY. Telemark: Bamble, Rognsflaugane, boreonemoral, mixed forest on soil with high pH, 2 September 2010, K.-H. Larsson and S. Svantesson (O F110316*); Telemark: Tokke, Dalen, Huvestad, boreonemoral, mixed forest on soil with high pH, 28 September 2010, S. Svantesson and N. Svensson (O F110315*);

SLOVENIA. Radovljica: Triglav National Park, Pokljuka plateau, transition zone between secondary spruce forest (in parts with remnants of primary Fagus sylvatica/Acer pseudoplatanus forest) and natural Larix decidua stand with individual trees of Pinus mugo, Sorbus aucuparia and Salix sp., 1530 m a.s.l., 20 September 2012, U. Kõljalg (TU 115626*);

SWEDEN. Ångermanland: Edsele, Djupdalsmyran, Stordjupdalen, on Picea abies, 29 August 2002, K.-H. Larsson 11873* (GB 0087566).

UNITED STATES. Arizona: Fort Valley, Coconino, on Pinus ponderosa Laws., 21 September 1967, R. L. Gilbertson 7553 (holotype: ARIZ!, GenBank Acc. No. ITS: MK290732; isotype: SSMF 685–4578).

SH005338.07FU

Basidiome annual, resupinate, membranaceous, effused. Mature parts continuous, with a cottony texture. Hymenium smooth, brown. Immature parts discontinuous, byssoid, with a cottony texture. Subhymenium and hymenium of immature parts initially whitish-grey to whitish-grey brown, when more mature blue grey to brown grey. Subiculum thin, loose, fibrous, pale brown; often forms the outer edge of the basidiome, extending noticeably beyond the hymenium. All characters recorded in dried state.

Figure 10. 

Micromorphological features of P. atrofusca in KOH. Holotype: A, B basidiospores in frontal face C, D in lateral face.

Hyphal cords connecting to the edge of the basidiome and thinning out underneath; whitish to pale brown. Individual cords dimitic; formed by a sheathing layer of skeletal hyphae and two layers of generative hyphae; the outer generative hyphae thinner and the inner ones wider, the latter often swollen interseptally. Skeletal hyphae 1.1–1.4 (–1.5) μm wide, with a mean width of 1.3 μm. Outer generative hyphae (2.2) 2.3–2.9 μm wide, with a mean width of 2.6 μm. Inner generative hyphae (3.8) 3.9–5.3 (5.5) μm wide, with a mean width of 4.5 μm. All hyphae pale yellowish-brown in both KOH and water.

Hyphal system dimitic, clamp connections and reaction in Melzer’s reagent absent from all hyphae.

Subicular hyphae of two kinds: (1) generative hyphae noticeably long and straight, thick-walled; forming a loose tissue, in which (2) skeletal hyphae occur sparsely (most common in areas to where hyphal cords attach). Generative hyphae (1.7–) 1.8–2.8 μm wide, with a mean width of 2.3 μm; pale yellowish-brown to yellowish-brown in both KOH and water. Skeletal hyphae with the same width and colour as in the hyphal cords.

Subhymenial hyphae often somewhat sinuous, thin to thick-walled; forming a rather dense tissue. Individual hyphae (1.8–) 2.1–3.0 μm wide, with a mean width of 2.5 μm; hyaline to pale green in KOH, blue green in the presence of air; hyaline to pale blue green in water, with strongly granular contents.

Basidia with four slightly curved sterigmata, occasionally two-sterigmate; clavate to narrowly clavate, sometimes clavopedunculate, thin-walled, with one-three slight constrictions. Dimensions: (33–) 34–56 (–59) × (5.8–) 6.2–7.8 (7.9) μm; mean dimensions: 44 × 7.2 μm. Sterigmata 4.4–5.6 (–6.8) μm long, with a mean length of 5.1 μm. Colours and reactions the same as for the subhymenial hyphae, but in addition often with granular contents in KOH.

Cystidial organs lacking.

Basidiospores in frontal face generally with a subcircular basic shape and an angular to nodulose or sometimes star or cross-shaped outline, covered in bi- or trifurcate, sometimes singularly attached, echinuli. Nearly all spores with five distinct, square lobes, but depending on the precise angle sometimes perceived as three; four-lobed spores occasionally occurring; abnormally large spores originating from two-sterigmate basidia infrequently seen. Frontal dimensions: (6.1–) 6.2–7.0 (–7.1) × (5.8–) 6.3–7.2 (–7.3) μm; mean dimensions: 6.6 × 6.8 μm; Q-value: 0.9–1.0; mean Q-value: 1.0. Echinuli 0.6–0.9 (–1.1) μm long, with a mean length of 0.8 μm. Lateral face ellipsoid to ovoid, usually with evenly rounded edges, sometimes with one-three lobes. Lateral dimensions: 6.3–6.9 (–7.3) × (4.0–) 4.1–4.8 (–5.0) μm; mean dimensions: 6.5 × 4.4 μm; Q-value: (1.3–) 1.4–1.6; mean Q-value: 1.5. Colour in both KOH and water pale brownish-yellow to pale blue green; inamyloid.

Chlamydospores lacking.

The only specimen recorded to date of P. atrofusca is the type collection, which was collected on wood of Pinus ponderosa. Available UNITE sequences originate from root tips of Rhododendron decorum (Kõljalg et al. 2005, Nilsson et al. 2019).

Basidiome encountered in: United States. Soil or root tip samples confirm presence also in: China.

Within the P. tristis group, the basidiome of P. atrofusca can be recognised by its hyphal cords and skeletal hyphae. These features make it unique within the group and the risk for confusion with any other described species should be small. Outside the P. tristis group, P. rhizopunctata is somewhat similar, but differs from P. atrofusca by the presence of chlamydospores on its hyphal cords.

ESTONIA. Valga: Otepää, Trommi, 12 September 2012, U. Kõljalg (holotype: TU 115609!, GenBank Acc. No. ITS: MK290714).

SH005336.07FU

The name refers to the middling morphological characters of the species, relative to other species in the P. tristis group.

Basidiomata annual, resupinate, membranaceous, effused to approximately ten centimetres in diameter. Mature parts continuous, with a rather firm, fibrous and compact, yet quite soft and elastic texture when dried. Hymenium smooth, but sometimes strongly undulating; brown with a reddish hue, both when fresh and when dried. Immature parts discontinuous, byssoid, with a cottony texture when dried. Subhymenium and hymenium of immature parts blue to greenish-blue when fresh and pale blue grey or blue grey to grey brown when dried. Subiculum well developed, loose, fibrous, pale brown to pale orange brown; forms the outer edge of basidiomata, extending noticeably beyond the hymenium.

Figure 11. 

Morphological features of P. media, mounted in KOH and macroscopically. A, B basidiospores in frontal face (TU 115608) C in lateral face (TU 115608) D subicular hyphae (TU 115608) E younger basidiome (TU 115608) F mature basidiome (holotype).

Hyphal cords lacking, but loose bundles of subicular hyphae sometimes present.

Hyphal system monomitic, clamp connections absent from all hyphae.

Subicular hyphae noticeably long and straight, thick-walled; forming a loose tissue. Individual hyphae (3.6–) 3.7–5.0 (–5.4) μm wide, with a mean width of 4.1–4.6 μm; orange brown to brown in both KOH and water.

Subhymenial hyphae often somewhat sinuous, thin to thick-walled; forming a rather dense tissue. Individual hyphae (3.2–) 3.4–5.6 (–5.7) μm wide, with a mean width of 4.3–4.4 μm; pale brown, pale orange brown, pale greenish-brown or hyaline in KOH, blue green in the presence of air; orange green to brown in water, with strongly granular contents. Some subhymenial hyphae with a pink colour in water and an amyloid reaction.

Encrustation granular, probably amyloid (hard to observe due to the colour); blackish in KOH, dark blue green in the presence of air; blackish in water; scattered in occurrence on the upper parts of subhymenial hyphae and on the lower parts of basidia.

Basidia with four slightly curved sterigmata, occasionally two-sterigmate; clavate or sometimes narrowly clavate or clavopedunculate, thin-walled, with one-three slight constrictions. Dimensions: (57–) 58–84 (–87) × (8.8–) 9.6–11.8 (–12.5) μm; mean dimensions: 74–77 × 10.2–10.7 μm. Sterigmata (9.4–) 9.5–11.4 (–11.7) μm long, with a mean length of 10.0–10.8 μm. Colours and reactions the same as for the subhymenial hyphae, but in addition often with granular contents in KOH.

Cystidial organs lacking.

Basidiospores in frontal face generally with a subcircular basic shape and an angular to nodulose or sometimes cross-shaped outline, covered in bi- or trifurcate, sometimes singularly attached, echinuli. A majority of the spores with three-six indistinct corners to distinct, square lobes; unlobed subellipsoid spores infrequently occurring, as well as abnormally large spores originating from two-sterigmate basidia. Frontal dimensions: (7.8–) 8.0–9.5 × (8.3–) 8.5–9.9 (–10.1) μm; mean dimensions: 8.9–9.3 × 9.2–9.8 μm; Q-value: 0.9–1.0; mean Q-value: 1.0. Echinuli (0.8–) 0.9–1.6 μm long, with a mean length of 1.1–1.2 μm. Lateral face ellipsoid, usually with evenly rounded edges, sometimes with one-three lobes. Lateral dimensions: (8.8–) 8.9–9.6 × (6.6–) 7.0–7.9 μm; mean dimensions: 9.1–9.4 × 7.3–7.6 μm; Q-value: 1.2–1.3; mean Q-value: 1.2–1.3. Colour in KOH pale brown to brown or pale orange brown to orange brown, in the presence of air sometimes blue green; in water orange brown to brown; inamyloid.

Chlamydospores lacking.

P. media has been found to form ectomycorrhiza with at least Betula pendula, Larix decidua and Picea glauca (Kõljalg et al. 2005, Nilsson et al. 2019).

Basidiomata encountered in: Estonia. Soil or root tip samples confirm presence also in: Canada, Italy and Russia.

Within the P. tristis group, the basidiomata of P. media can be recognised by their lack of hyphal cords and skeletal hyphae and their soft, yet rather firm and compact and ± elastic texture after drying, bluish to greenish colour of immature parts, narrow subicular hyphae, brown mature hymenium, long, laterally wide, angular-nodulose spores and subhymenial hyphae that are of ± the same width as the subicular hyphae. Pseudotomentella pinophila and P. pluriloba can appear similar, but the spores of P. pinophila are laterally narrower and generally star-shaped, while P. pluriloba has wider subicular hyphae, larger spores and subhymenial hyphae that are noticeably narrower than the subicular hyphae.

ESTONIA. Valga: Otepää, Trommi, 12 September 2012, U. Kõljalg (TU 115608*).

SWEDEN. Småland: Jönköping, Svarttorp, Ramlaklint, boreonemoral, mixed, old-growth forest, on soil with intermediate pH, 12 September 2016, S. Svantesson 358 (holotype: GB!, GenBank Acc. No. ITS: MK290708).

SH005337.07FU

The name refers to the ectomycorrhizal association of the species, which often seems to be with Pinus.

Basidiomata annual, resupinate, membranaceous, effused – often to several tens of centimetres in diameter. Mature parts continuous, with a cottony texture when fresh and a rather firm, fibrous and compact, yet quite soft and elastic texture when dried. Hymenium smooth, but sometimes strongly undulating; pale brown to pale greenish-brown when fresh, pale reddish-brown when dried. Immature parts discontinuous, byssoid with a cottony texture, both when fresh and when dried. Subhymenium and hymenium of immature parts blue to grey when fresh, pale blue or blue grey to dark blue grey or brown grey, sometimes with a green hue, when dried. Subiculum well-developed, loose, fibrous, pale orange brown; often forms the outer edge of basidiomata, extending noticeably beyond the hymenium.

Figure 12. 

Morphological features of P. pinophila, mounted in KOH and macroscopically. A, B basidiospores in frontal face (holotype) C in lateral face (O F110330) D encrusted subhymenial hyphae (O F110305) E subicular hyphae (O F110330) F mature basidiome (SS418).

Hyphal cords lacking, but loose bundles of subicular hyphae sometimes present.

Hyphal system monomitic, clamp connections absent from all hyphae.

Subicular hyphae noticeably long and straight, thick-walled; forming a loose tissue. Individual hyphae 3.0–4.9 μm wide, with a mean width of 3.6–4.1 μm; pale orange brown to pale pinkish-brown in both KOH and water.

Subhymenial hyphae often somewhat sinuous, thin to thick-walled; forming a rather dense tissue. Individual hyphae (3.1–) 3.2–4.7 (–5.2) μm wide, with a mean width of 3.9–4.0 μm; hyaline to pale green or occasionally pale brown in KOH, blue green in the presence of air; pale green to pale orange in water, with strongly granular contents; sometimes with an amyloid reaction in the cell walls.

Encrustation granular, amyloid; bluish-black in both KOH and water; common to rare, usually scattered in occurrence on the upper parts of subhymenial hyphae and on the lower parts of basidia.

Basidia with four slightly curved sterigmata, occasionally two-sterigmate; clavate to narrowly clavate, sometimes clavopedunculate, thin-walled, with one-three slight constrictions. Dimensions: (53–) 58–74 (–83) × (9.0–) 9.1–11.7 (–12.1) μm; mean dimensions: 65–67 × 9.9–10.3 μm. Sterigmata (8.2–) 8.8–10.5 (–11.9) μm long, with a mean length of 9.6–10.0 μm. Colours and reactions the same as for the subhymenial hyphae, but in addition often with granular contents in KOH.

Cystidial organs lacking.

Basidiospores in frontal face commonly with a subcircular basic shape and a roundedly star-shaped, sometimes roundedly cross-shaped or angular to nodulose outline, covered in bi- or trifurcate, occasionally singularly attached, echinuli. Lobes distinct, rounded to square; predominantly five, but commonly also three or four; six-lobed or subellipsoid, unlobed spores and spores with corners instead of lobes infrequently occurring, as well as abnormally large spores originating from two-sterigmate basidia. Frontal dimensions: (7.7–) 7.9–10.2 (–10.3) × (7.7–) 8.3–10.1 (–10.2) μm; mean dimensions: 8.6–9.1 × 8.8–9.4 μm; Q-value: 0.9–1.1; mean Q-value: 1.0. Echinuli (0.6–) 0.8–1.4 (–1.5) μm long, with a mean length of 0.9–1.1 μm. Lateral face ellipsoid to ovoid, usually with evenly rounded edges, sometimes with angular edges or one-three lobes. Lateral dimensions: (8.2–) 8.3–9.7 (–9.8) × (5.7–) 5.8–6.8 (–7.0) μm; mean dimensions: 8.7–9.0 × 6.3–6.6 μm; Q-value: 1.3–1.6; mean Q-value: 1.3–1.4. Colour in KOH pale green to orange brown, in the presence of air sometimes with a blue green reaction; in water pale green to orange brown or brown; occasionally amyloid.

Chlamydospores lacking.

Data on habitat are scarce to date, but recent Scandinavian collections have been made in old coniferous or mixed forests on soil with high pH. Pseudotomentella pinophila has been found to form ectomycorrhiza with at least Pinus densiflora, Pinus massoniana, Pinus sylvestris and Pinus thunbergii (Kõljalg et al. 2005, Nilsson et al. 2019). It should be noted however that, although the only hitherto documented hosts of P. pinophila belong to the genus Pinus and P. sylvestris has indeed been present at nearly all Nordic localities of collection, a few of these collections were made at localities where Pinus was not recorded as a possible host.

Basidiomata encountered in: Norway and Sweden. Soil or root tip samples confirm presence also in: China and Republic of Korea.

Within the P. tristis group, the basidiomata of P. pinophila can be recognised by their lack of hyphal cords and skeletal hyphae and their soft, yet rather firm and compact and ± elastic texture after drying, bluish to greenish colour of immature parts, narrow subicular hyphae, brown mature hymenium, long, laterally narrow and commonly star-shaped spores. Pseudotomentella sciastra, P. pluriloba and P. media can appear similar. Even though P. sciastra has star-shaped spores, it also has wider subicular hyphae than P. pinophila and, while P. pluriloba and P. media both share the characters of narrow hyphae, long spores and hymenia that are brown when mature with P. pinophila, they differ by having angular-nodulose spores, which are also laterally wider than the spores of P. pinophila.

NORWAY. Akershus: Asker, Skaugumåsen, boreonemoral, mixed forest on on soil with high pH, 23 September 2010, S. Svantesson (O F110327); Oslo (county): Oslo (municipality), Bygdøy, Hengsåsen, boreonemoral, mixed forest on soil with high pH, 22 September 2010, S. Svantesson (O F110328*); Oslo (county): Oslo (municipality), Gressholmen, boreonemoral, mixed forest on soil with high pH, 20 September 2010, S. Svantesson (O F110329); Telemark: Bamble, Rognsflaugane, boreonemoral, mixed forest on soil with high pH, 2 September 2010, K.-H. Larsson and S. Svantesson (O F110305); Akershus: Asker, Esvika, Løkenes, boreonemoral, mixed forest on soil with high pH, 15 August 2010, K.-H. Larsson and N. Svensson (O F110330*);

SWEDEN. Västergötland: Götene, Österplana, Hönsäter, coniferous forest on soil with high pH, 14 September 2017 S. Svantesson 418*, 419* (GB); Öland: Borgholm, Böda, Hagudden, mixed forest on soil with high pH, 5 October 2017 S. Svantesson 440* (GB).

FINLAND. Uusimaa: Loviisa, Rutosinpyhtää, Marinkylä, rotten trunk on the ground (Picea), 30 September 2010, U. Söderholm 4263 (holotype: H 6018127!, GenBank Acc. No. ITS: MK290698).

SH030565.07FU

The name refers to the several lobes of the spores.

Basidiomata annual, resupinate, membranaceous, effused to approximately ten centimetres in diameter. Mature parts continuous, with a cottony texture when fresh and a rather firm, fibrous and compact, yet quite soft and elastic texture when dried. Hymenium smooth, but sometimes strongly undulating; brown to purplish-brown when fresh, reddish-brown when dried. Immature parts discontinuous, byssoid with a cottony texture, both when fresh and when dried. Subhymenium and hymenium of immature parts blue when fresh, blue grey to brown grey after drying. Subiculum well developed, loose, fibrous, brown with an orange hue; forms the outer edge of basidiomata, extending noticeably beyond the hymenium.

Figure 13. 

Morphological features of P. pluriloba, mounted in KOH and macroscopically. Holotype: A, B, C basidiospores in frontal face D in lateral face E subicular hyphae F mature basidiome.

Hyphal cords lacking, but loose bundles of subicular hyphae sometimes present.

Hyphal system monomitic, clamp connections absent from all hyphae.

Subicular hyphae noticeably long and straight, thick-walled; forming a loose tissue. Individual hyphae (3.9–) 4.0–5.9 (–6.8) μm wide, with a mean width of 6.8–5.1 μm; orange brown in both KOH and water.

Subhymenial hyphae often somewhat sinuous, thin to thick-walled; forming a rather dense tissue. Individual hyphae (2.7–) 2.9–5.3 (–5.4) μm wide, with a mean width of 4.0–4.2 μm; pale orange green to hyaline in KOH, blue green in the presence of air; pale orange green to hyaline in water, with strongly granular contents.

Encrustation granular, amyloid, concolourous with the hyphae in both KOH and water; usually common and scattered in occurrence on the upper parts of subhymenial hyphae and on the lower parts of basidia.

Basidia with four slightly curved sterigmata, occasionally two-sterigmate; clavate to narrowly clavate, sometimes clavopedunculate, thin-walled, with one-three slight constrictions. Dimensions: (55–) 58–87 (–94) × (10.3–) 10.7–13.3 (–13.4) μm; mean dimensions: 68–73 × 11.8–12.1 μm. Sterigmata (9.8–) 10.1–13.7 (–14.5) μm long, with a mean length of 11.5–12.3 μm. Colours and reactions the same as for the subhymenial hyphae, but in addition often with granular contents in KOH.

Cystidial organs lacking.

Basidiospores in frontal face generally with a subcircular basic shape and an angular to nodulose or sometimes cross-shaped outline, covered in bi- or trifurcate, sometimes singularly attached, echinuli. Nearly all spores with three-five distinct corners or rounded to square lobes; unlobed subcircular, unlobed subellipsoid or rounded, heart-shaped spores infrequently occurring, as well as abnormally large spores originating from two-sterigmate basidia. Frontal dimensions: (9.0–) 9.1–10.8 (–10.9) × (9.2–) 9.3–10.9 (–11.1) μm; mean dimensions: 9.8 × 10.2 μm; Q-value: 0.9–1.0 (–1.1); mean Q-value: 1.0. Echinuli (0.9–) 1.0–1.9 μm long, with a mean length of 1.4 μm. Lateral face ellipsoid, usually with evenly rounded edges, rarely with one-three lobes. Lateral dimensions: 9.0–10.4 (–10.8) × (6.7–) 6.8–8.5(8.6) μm; mean dimensions: 9.6–9.8 × 7.5–7.6 μm; Q-value: 1.2–1.4; mean Q-value: 1.3. Colour in KOH pale orange green, in the presence of air often with a pale blue green reaction; in water pale orange; occasionally amyloid.

Chlamydospores lacking.

Data on habitat are scarce to date, but recent Scandinavian collections have been made in mature to old coniferous or mixed forests on soil with intermediate pH. Pseudotomentella pluriloba has been found to form ectomycorrhiza with at least Pseudotsuga menziesii (Kõljalg et al. 2005, Nilsson et al. 2019).

Basidiomata encountered in: Finland and Sweden. Soil or root tip samples confirm presence also in: Canada and the United States.

Within the P. tristis group, the basidiomata of P. pluriloba are recognised by their lack of hyphal cords and skeletal hyphae and their soft, yet rather firm and compact and ± elastic texture after drying, bluish to greenish colour of immature parts, wide subicular hyphae and noticeably narrower subhymenial hyphae, long, moderately lobed spores and amyloid encrustation on subhymenial hyphae and basidia. Pseudotomentella abundiloba, P. alobata and P. media can appear similar, but P. media differs by having smaller spores and narrower subicular hyphae which are ± the same width as its subicular hyphae, while P. abundiloba and P. alobata have frontally narrower spores with different lobation than P. pluriloba, as well as wider subicular hyphae and shorter sterigmata.

SWEDEN. Öland: Borgholm, Böda, Trollskogen, mixed forest on soil with intermediate pH, 5 October 2017, S. Svantesson 439* (GB).

SWEDEN. Västergötland: Götene, Medelplana, Eriksberg, boreonemoral, mixed forest on soil with high pH, 17 October 2016, S. Svantesson 413 (holotype: GB!, GenBank Acc. No. ITS: MK290674).

SH030562.07FU

The name refers to the appearance of the spores, which often have rounded or weakly pronounced lobes and comparably short echinuli.

Basidiomata annual, resupinate, membranaceous, effused – often to several tens of centimetres in diameter. Mature parts continuous, with a cottony texture when fresh and a rather firm, fibrous and compact, yet quite soft and elastic texture when dried. Hymenium smooth, but sometimes strongly undulating; brown to greenish-brown when fresh, concolourous when dried, but then sometimes with a red hue. Immature parts discontinuous, byssoid with a cottony texture, both when fresh and when dried. Subhymenium and hymenium of immature parts blue to blue green or grey when fresh, pale blue grey to grey blue when dried. Subiculum well developed, loose, fibrous, pale brown to pale orange brown; often forms the outer edge of basidiomata, extending noticeably beyond the hymenium.

Figure 14. 

Morphological features of P. rotundispora, mounted in KOH and macroscopically. A (holotype) B (SS393) C (holotype) basidiospores in frontal face D in lateral face (holotype) E subicular hyphae (holotype) F mature basidiome (holotype).

Hyphal cords lacking, but loose bundles of subicular hyphae sometimes present.

Hyphal system monomitic, clamp connections absent from all hyphae.

Subicular hyphae noticeably long and straight, thick-walled; forming a loose tissue. Individual hyphae 3.0–4.4 (–4.6) μm wide, with a mean width of 3.4–3.8 μm; brown to orange brown in both KOH and water.

Subhymenial hyphae often somewhat sinuous, thin to thick-walled; forming a rather dense tissue. Individual hyphae (2.7–) 3.0–4.6 (–6.3) μm wide, with a mean width of 3.6–3.7 μm; pale brown to brown in KOH, often with orange or green hues, blue green in the presence of air; brown to orange brown in water, with strongly granular contents; some subhymenial hyphae with a pink colour in water and an amyloid reaction in Melzer’s reagent.

Encrustation granular, probably amyloid (hard to observe due to the colour); blackish in KOH, dark blue green in the presence of air; blackish in water; scattered in occurrence on the upper parts of subhymenial hyphae and on the lower parts of basidia.

Basidia with four slightly curved sterigmata, occasionally two-sterigmate; clavate or sometimes narrowly clavate or clavopedunculate, thin-walled, with one-three slight constrictions. Dimensions: 40–66 (–69) × 8.2–10.6 (–11.1) μm; mean dimensions: 54–60 × 8.8–9.7 μm. Sterigmata (6.6–) 7.4–11.0 (–11.5) μm long, with a mean length of 8.5–10.2 μm.

Colours and reactions the same as for the upper parts of subhymenial hyphae, but in addition often with granular contents in KOH.

Cystidial organs lacking.

Basidiospores in frontal face very variable. Generally with a subcircular basic shape and an angular, nodulose, star-shaped or occasionally cross-shaped outline, covered in bi- or trifurcate, sometimes singularly attached, echinuli. Nearly all spores with three-seven, commonly three or five, indistinct corners to distinct, usually rounded lobes; spores with angular or square lobes infrequently occurring, as well as abnormally large spores originating from two-sterigmate basidia. Frontal dimensions: (6.7–) 7.0–8.2 (–8.4) × 7.0–8.6 μm; mean dimensions: 7.5–7.6 × 7.7–7.9 μm; Q-value: 0.9–1.1; mean Q-value: 1.0. Echinuli 0.5–1.1 (–1.3) μm long, with a mean length of 0.8 μm. Lateral face ellipsoid, usually with evenly rounded edges, sometimes with one-three lobes. Lateral dimensions: 7.0–8.2 (–8.3) × (5.2–) 5.3–6.0 (–6.1) μm; mean dimensions: 7.6–7.9 × 5.6–5.7 μm; Q-value: 1.3–1.5; mean Q-value: 1.4. Colour in KOH pale brown to brown or pale orange brown to orange brown, in the presence of air sometimes with a blue green reaction; in water brown to orange brown; occasionally with an amyloid reaction.

Chlamydospores lacking.

Data on habitat are scarce to date, but recent Scandinavian collections have been made in old, coniferous, deciduous or mixed forests on soil with high pH. Pseudotomentella rotundispora has been found to form ectomycorrhiza with at least Castanea sp. and Populus tremula (Kõljalg et al. 2005, Nilsson et al. 2019).

Basidiomata encountered in: Estonia, Norway and Sweden. Soil or root tip samples confirm presence also in: Austria, Italy and the United Kingdom.

Within the P. tristis group, the basidiomata of P. rotundispora can be recognised by their lack of hyphal cords and skeletal hyphae and their soft, yet rather firm and compact and ± elastic texture after drying, bluish to greenish colour of immature parts, narrow subicular hyphae and short spores. The other species within the group can appear similar, but have either wider hyphae, longer spores or both.

ESTONIA. Lääne: Hanila, Puhtu-Laelatu Nature Reserve, Puhtu peninsula, deciduous forest with Populus, Tilia, Quercus and Picea, 11 August 2005, U. Kõljalg (TU 100138*);

NORWAY. Oslo (county): Oslo (municipality), Bygdøy, Dronningberget, mixed forest on soil with high pH, 30 September 2017, K.-H. Larsson 17682* (O);

SWEDEN. Västergötland: Götene, Medelplana, Eriksberg, boreonemoral, mixed forest on soil with high pH, 17 October 2016, S. Svantesson 393*, 394* (GB).

SWEDEN. Småland: Jönköping, Svarttorp, Ramlaklint, boreonemoral, mixed, old-growth forest, on soil with intermediate pH, 12 September 2016, S. Svantesson 359 (holotype: GB!, GenBank Acc. No. ITS: MK290686).

SH030554.07FU

The name refers to the dark, star-like appearance of the spores.

Basidiomata annual, resupinate, membranaceous, effused – often to several tens of centimetres in diameter. Mature parts continuous, with a cottony texture when fresh and a rather firm, fibrous and compact, yet quite soft and elastic texture when dried. Hymenium smooth, but sometimes strongly undulating; blue grey when fresh and brown with a pinkish hue when dried. Immature parts discontinuous, byssoid with a cottony texture, both when fresh and when dried. Subhymenium and hymenium of immature parts blue grey when fresh or occasionally green or even yellow; blue grey to brown grey when dried. Subiculum well developed, loose, fibrous, pale orange brown to brown; often forms the outer edge of basidiomata, extending noticeably beyond the hymenium.

Figure 15. 

Morphological features of P. sciastra, mounted in KOH and macroscopically. A basidiospore in frontal face (O F110317) B in frontal and lateral faces (O F110317) C in lateral face (O F110317) D subicular hyphae (O F110317) E (SS420) F (SS312) mature basidiomata.

Hyphal cords lacking, but loose bundles of subicular hyphae sometimes present.

Hyphal system monomitic, clamp connections absent from all hyphae.

Subicular hyphae noticeably long and straight, thick-walled; forming a loose tissue. Individual hyphae (3.9–) 4.4–6.6 (–6.8) μm wide, with a mean width of 5.0–5.8 μm; brown to orange brown in KOH, orange brown in water.

Subhymenial hyphae often somewhat sinuous, thin to thick-walled; forming a rather dense tissue. Individual hyphae 2.9–5.0 (–6.0) μm wide, with a mean width of 3.8–4.0 μm; hyaline to pale green in KOH, blue green in the presence of air; pale orange green to pale yellowish-green in water, with strongly granular contents.

Encrustation granular, probably amyloid (hard to observe due to the colour); blackish-brown in KOH, dark blue green in the presence of air; blackish-brown in water; scattered in occurrence on the upper parts of subhymenial hyphae and on the lower parts of basidia.

Basidia with four slightly curved sterigmata, occasionally two-sterigmate; clavate to narrowly clavate, sometimes clavopedunculate, thin-walled, with one-three slight constrictions. Dimensions: 42–67 (–68) × 7.3–9.0 (–9.3) μm; mean dimensions: 54–55 × 7.8–8.1 μm. Sterigmata (6.0–) 6.3–8.9 (–9.1) μm long, with a mean length of 7.4–7.9 μm. Colours and reactions the same as for the subhymenial hyphae, but in addition often with granular contents in KOH.

Cystidial organs lacking.

Basidiospores in frontal face with a subcircular basic shape and a star- or cross-shaped, sometimes angular to nodulose outline, covered in bi- or trifurcate, sometimes singularly attached, echinuli. Nearly all spores with four-six distinct, rounded to more often square lobes or rarely corners; abnormally large spores originating from two-sterigmate basidia infrequently occurring. Frontal dimensions: (6.0–) 6.1–7.9 (–8.1) × 6.3–8.2 μm; mean dimensions: 6.6–7.3 × 6.7–7.7 μm; Q-value: 0.9–1.1; mean Q-value: 1.0. Echinuli (0.5–) 0.6–1.2 (–1.4) μm long, with a mean length of 0.8–0.9 μm. Lateral face ellipsoid to ovoid, with evenly rounded edges or one-three lobes. Lateral dimensions: (6.2–) 6.5–7.7 (–8.0) × (4.3–) 4.4–6.0 (–6.2) μm; mean dimensions: 6.8–7.3 × 4.6–5.4 μm; Q-value: 1.2–1.6 (–1.7); mean Q-value: 1.3–1.5. Colour in KOH brown to yellow brown, in the presence of air often with a green to blue green reaction; in water pale greenish to pale greenish-orange; occasionally amyloid.

Chlamydospores lacking.

Recent Scandinavian collections have been made in mature to old coniferous, deciduous or mixed forests on soil with intermediate to high pH. Pseudotomentella sciastra has been found to form ectomycorrhiza with at least Castanea sativa, Cedrus libani, Neottia ovata, Picea abies and Quercus sp. (Kõljalg et al. 2005, Nilsson et al. 2019).

Basidiomata encountered in: Estonia, Finland, Norway, Sweden, Turkey and the United Kingdom. Soil or root tip samples confirm presence also in: the Czech Republic, Mexico, Portugal (Madeira) and the United States.

All studied European specimens previously identified as P. atrofusca belong to P. sciastra. The two species display considerable morphological differences (see key).

Within the P. tristis group, the basidiomata of P. sciastra are recognised by their lack of hyphal cords and skeletal hyphae and their soft, yet rather firm and compact and ± elastic texture after drying, bluish to greenish colour of immature parts, wide subicular hyphae and small, star-shaped spores. Pseudotomentella pinophila is similar, but has narrower subicular hyphae and larger spores.

ESTONIA. Ida-Virumaa: Illuka, Puhatu Nature Reserve, Poruni primeval forest, wetlands, 1 October 2006, U. Kõljalg (TU 100644*); [Saare,] Saarema, Kihelkonna, Hülgera, Sampling area G4422, 25 September 2015, A. Saitta (TU 124211*, TU 124213*);

FINLAND. Etelä-Häme: Jyväskylä, Korpilahti, Oittila, on dead trunk of Ulmus glabra, 3 September 2014, U. Söderholm 4755 (H 6052710); Kanta-Häme: Lammi, Lammi Biological Station, Leib-rich forest, 12 September 2001, K.-H. Larsson (TU 108754*);

NORWAY. Oslo (county): Oslo (municipality), Bygdøy, Hengsåsen, boreonemoral, mixed forest on soil with high pH, 16 August 2010, K.-H. Larsson and N. Svensson (O F110317*); Østfold: Moss, Jeløya, boreonemoral, mixed forest on soil with high pH, 26 September 2010, S. Svantesson and N. Svensson (O F110318*); Oppland: Dovre, Grimsdalen, Austre Stakkstosætra, Pinus sylvestris forest, 26 August 2010, K.-H. Larsson and S. Svantesson (O F110301); Vestfold: Larvik, Kvelde, Jordstøyp, boreonemoral, mixed forest on soil with intermediate pH, 1 October 2010, K.-H. Larsson (O F110302); Ibidem, on soil with high pH, 1 September 2010, K.-H. Larsson and S. Svantesson (O F110303, F110304); Aust-Agder, Risør, Glupedalen, boreonemoral, mixed forest on soil with high pH, 10 September 2010, S. Svantesson and N. Svensson (O F110319, F110320, F110321); Aust-Agder: Tvedestrand, Eidbo, boreonemoral, mixed forest on soil with intermediate pH, 10 September 2010, S. Svantesson and N. Svensson (O F110322*); Oslo (county): Oslo (municipality), Gressholmen, boreonemoral, mixed forest on soil with high pH, 20 September 2010, S. Svantesson (O F110323, F110324); Oslo (county): Oslo (municipality), Killingen, boreonemoral, mixed forest on soil with high pH, 22 September 2010, S. Svantesson (O F110325); Buskerud: Ringerike, Ulltveit Nature Reserve, boreonemoral, coniferous forest on soil with high pH, 25 September 2010, S. Svantesson and N. Svensson (O F110326);

SWEDEN. Småland: Jönköping, Svarttorp, Ramlaklint, boreonemoral, mixed, old-growth forest, on soil with intermediate pH, 12 September 2016, S. Svantesson 360 (GB); Bohuslän: Tanum (municipality), Tanum (parish), Lammön, boreonemoral, deciduous forest on soil with high pH, 6 September 2016, S. Svantesson 312* (GB); Västergötland: Göteborg, Askim, Årekärrslunden, 24 October 2015, K.-H. Larsson 17308b* (GB); Dalsland, Mellerud, Skållerud, Österbo, mixed forest on soil with high pH, 20 September 2017, S. Svantesson 420* (GB); Ibidem, Norgekullen SW, coniferous forest on soil with high pH, 20 September 2017, S. Svantesson 423* (GB);

TURKEY. [Antalya: Elmalı,] Ciglikara, 2009, L. Tedersoo (TU 110153*); [Isparta:] Yukan-Gökdere [=Yukarı Gökdere], 2009, L. Tedersoo (TU 110113*);

UNITED KINGDOM. Scotland, Aberdeenshire: Inverurie, Burnhervie, in a small group of planted Populus trees, 16 September 2005, I. J. Alexander (TAA 187322*).

Hypochnus subfuscus ssp. tristis P.Karst., Meddeland. Soc. Fauna Fl. Fenn. 9: 71 (1883). Hypochnus tristis (P.Karst.) P.Karst. Bidrag Kännedom Finlands Natur Folk. 48: 440 (1889). Tomentella tristis (P.Karst.) Höhn. & Litsch., Sitzungsber. Kaiserl. Akad. Wiss., Wien. Math.-Naturwiss. Cl., Abt. 1 115: 1572 (1906). Type. FINLAND. Tavastia australis [= Etelä-Häme]: Tammela, Mustiala, ad Betulam, 19 August 1865, P.A. Karsten (lectotype: Herbarium P. A. Karsten 3036 [H 6018703]!, designated by M.J. Larsen in Nova Hedwigia 22(1–2): 613 (1971) [1972]); SWEDEN. Västerbotten: Vännäs, Orrböle, boreal, mixed forest on soil with high pH, 28 August 2015, S. Svantesson 193 (EPITYPE: GB!, here designated, MycoBank Typification No. MBT384911, GenBank Acc. No. ITS: MK290679).

Figure 16. 

Morphological features of P. tristis, mounted in KOH and macroscopically. A (LK54/13) B (lectotype) C (epitype), basidiospores in frontal face D (epitype) E (TAA 159485) in lateral face F subicular hyphae (epitype) G young basidiome (TU 115439) H mature basidiome (TU 115642).

Hypochnopsis fuscata P.Karst., Bidrag Kännedom Finlands Natur Folk 48: 443 (1889). Hypochnus fuscatus (P.Karst.) Sacc., Syll. fung. 9: 244 (1891). Type. FINLAND. Tavastia australis: Messuby [Tavastia australis = Etelä-Häme; Messuby is part of the city of Tampere], September 1860, P.A. Karsten (lectotype: Herbarium P.A. Karsten 770 [H 6059014]!, designated by M.J. Larsen in Nova Hedwigia 22(1–2): 616 (1971) [1972]); SWEDEN. Västerbotten: Vännäs, Orrböle, boreal, mixed forest on ground with high pH, 28 August 2015, S. Svantesson 193 (EPITYPE: GB!, here designated, MycoBank Typification No. MBT384955, GenBank Acc. No. ITS: MK290679).

SLOVAKIA [Hungary at the time of collection]. Prenčow, Sitno, infra filagorum, in trunco putr. Fagi, 11 September 1895, Andr. Kmet (holotype: S F15178!).

SH030560.07FU

Basidiomata annual, resupinate, membranaceous, effused – often to several tens of centimetres in diameter. Mature parts continuous, with a cottony texture when fresh and a rather firm, fibrous and compact, yet quite soft and elastic texture when dried. Hymenium smooth, but sometimes strongly undulating; blue grey to purplish-brown when fresh, blue grey or blue-greenish grey to brown, with a reddish hue, when dried. Immature parts discontinuous, byssoid with a cottony texture, both when fresh and when dried. Subhymenium and hymenium of immature parts blue green, blue or blue grey when fresh and pale grey blue or pale blue grey to grey blue or blue grey when dried, sometimes with a green hue. Subiculum well developed, loose, fibrous, orange brown; often forms the outer edge of basidiomata, extending noticeably beyond the hymenium.

Hyphal cords lacking, but loose bundles of subicular hyphae sometimes present.

Hyphal system monomitic, clamp connections absent from all hyphae.

Subicular hyphae noticeably long and straight, thick-walled; forming a loose tissue. Individual hyphae (4.5) 4.6–7.4 μm wide, with a mean width of 5.4–6.2 μm; orange brown to dark brown in KOH, orange brown to brown in water.

Subhymenial hyphae often somewhat sinuous, thin to thick-walled; forming a rather dense tissue. Individual hyphae 3.2–6.2 (7.2) μm wide, with a mean width of 3.9–4.5 μm; pale orange brown to pale green in KOH, blue green in the presence of air; pale green to pale greenish-orange in water, with strongly granular contents.

Encrustation granular, probably amyloid (hard to observe due to the colour); blackish in KOH, dark blue green in the presence of air; blackish in water; scattered in occurrence on the upper parts of subhymenial hyphae and on the lower parts of basidia.

Basidia with four slightly curved sterigmata, occasionally two-sterigmate; clavate to narrowly clavate, sometimes clavopedunculate, thin-walled, with one-three slight constrictions. Dimensions: 51–76 (–84) × (8.1) 8.3–13.7 (–14.6) μm; mean dimensions: 56–62 × 9.6–11.6 μm. Sterigmata (8.0) 8.3–11.3 (13.3) μm long, with a mean length of 9.4–10.2 μm. Colours and reactions the same as for the subhymenial hyphae, but in addition often with granular contents in KOH.

Cystidial organs lacking.

Basidiospores in frontal face generally with a subcircular basic shape and an unlobed, angular, weakly nodulose or sometimes cross-shaped outline, covered in bi- or trifurcate, occasionally singularly attached echinuli. A majority of the spores normally unlobed or with three-five indistinct corners to rounded lobes; subcircular spores with more pronounced, sometimes square lobes or ovoid to subellipsoid spores also common in some specimens; subcircular, six-lobed spores infrequently occurring, as well as abnormally large spores originating from two-sterigmate basidia. Frontal dimensions: 7.7–9.1 (9.2) × 8.0–9.2 (9.6) μm; mean dimensions: 8.3–8.6 × 8.4–8.8 μm; Q-value: 0.9–1.1; mean Q-value: 1.0–1.1. Echinuli (0.8) 0.9–1.9 μm long, with a mean length of 1.4 μm. Lateral face ellipsoid to narrowly ovoid or sometimes semicircular in shape, usually with evenly rounded edges, sometimes with one-three lobes. Lateral dimensions: (7.7) 8.0–9.0 × (6.0) 6.1–6.8 (7.0) μm; mean dimensions: 8.3–8.5 × 6.3–6.5 μm; Q-value: 1.2–1.4 (–1.5); mean Q-value: 1.3. Colour in KOH brown to orange brown, in the presence of air often with a blue green reaction; in water greenish-orange to orange brown; occasionally amyloid.

Chlamydospores lacking.

Data on habitat are scarce to date, but recent Scandinavian collections have been made in mature to old deciduous or mixed forests on soil with intermediate to high pH. Pseudotomentella tristis has been found to form ectomycorrhiza with at least Betula pendula and Fagus sylvatica (Kõljalg et al. 2005, Nilsson et al. 2019).

Basidiomata encountered in: Estonia, Finland, Norway, Slovakia, Slovenia and Sweden. Soil or root tip samples confirm presence also in: Germany.

We here select a Swedish specimen to serve as an epitype for both P. tristis and H. fuscata. This decision is based on four reasons: first, the present study has found P. tristis and H. fuscata to be conspecific; secondly, the lectotypes of these species were both collected in Finland (within the same county); thirdly we have found P. tristis to occur at several localities in both Finland and Sweden; and fourthly, the Swedish material chosen is both ampler and displays more variation with respect to maturity of the basidiome than the single available recent Finnish collection.

The type specimen of H. sitnensis was collected in Slovakia, i.e. far from the type locality of P. tristis. It displays the morphological characters of P. tristis, apart from the absence of an amyloid reaction in the encrusting material found on basidia and subhymenial hyphae. This might be an artefact of, for example, its drying conditions, time or intraspecific variation, but since the specimen is in too poor a condition to allow DNA sequencing with currently available methods, this cannot be ascertained. We therefore consider it a synonym of P. tristis and suggest it be epitypified in due course with locally sampled material that matches the type.

In the case of H. sitnensis, there is only one collection matching the locality and habitat description of the protologue as well as the collector stated. It predates the publication of the species. This collection must hence be regarded as a holotype.

P.A. Karsten 770 is the lectotype of H. fuscata, as designated by Larsen in Nova Hedwigia (1971), but his note has been placed in P.A. Karsten 769, which has created confusion amongst mycologists studying these specimens. Mature spores that fall within the morphological span of P. tristis can easily be found in all collections that match Karsten’s (1889) description of the species, with respect to locality and date. It would hence seem that the smooth, small, bluish spores he writes of in the protologue (see Introduction) probably were immature ones, studied in the presence of air.

Within the P. tristis group, basidiomata of P. tristis itself can be recognised by their lack of hyphal cords and skeletal hyphae and their soft, rather elastic texture after drying, bluish to greenish colour of immature parts, wide subicular hyphae, medium sized, commonly angular to nodulose spores and relatively long echinuli and sterigmata. Pseudotomentella tristoides is similar but has shorter echinuli and sterigmata, P. sciastra has smaller, star-shaped spores and H. rhacodium (only known from the type) has hard, brittle basidiomata after drying.

ESTONIA. Valga: Otepää, Kääriku, Välkjärve, 10 September 2012, U. Kõljalg (TU 115439*); Tartumaa: Võnnu, Terikeste, on fallen branch of Picea abies in mixed forest, 20 August 1996, U. Kõljalg (TAAM 159485*); Lääne: Vormsi, road from Diby to Norrby, deciduous forest with Betula and Corylus, 27 September 2008, U. Kõljalg (TU 108134*);

FINLAND. Kanta-Häme: Lammi, Lammi Biological Station, Leib-rich forest, 12 September 2001, U. Kõljalg (TU 108757*); Satakunta: Luvia, Säppi, on fallen decayed Betula, 11 September 2013, L. Kosonen 54/13* (TUR);

NORWAY. Møre og Romsdal: Nesset, Eikesdal, Ljåstranda, rich, deciduous forest, 18 September 2011, K.-H. Larsson 15084* (O); Oppland: Vinstra, Liadalen, rich, deciduous forest, 24 September 2013, K.-H. Larsson 16367* (O); Hedmark: Ringsaker, Liberget, 24 August 1984, K.-H. Larsson 5901 (GB 87563); Sogn og Fjordane: Stryn, Flostranda Nature Reserve, boreonemoral, deciduous forest on ground with high pH, 25 September 2013, K.-H. Larsson (O F110297*); Rogaland: Forsand, Rössdalen, boreonemoral, deciduous forest on ground with high pH, 29 September 2012, K.-H. Larsson and S. Svantesson (O F110298*); Oppland: Nord-Fron, Liadalane Nature Reserve, boreonemoral, deciduous forest on ground with intermediate pH, 24 September 2013, K.-H. Larsson (O F110299, F110300*);

SLOVENIA. Upravna enota Kočevje: Rahjenavski Rog virgin forest reserve, S and E edge of the reserve, beech-silver fir old growth forest, 21 September 2012, S. Kõljalg; U. Kõljalg (TU 115642*);

SWEDEN. Västerbotten: Vännäs (municipality), Vännäs (parish), Orrböle, boreal, mixed, secondary, mature forest, on ground with high pH, 28 August 2015, S. Svantesson 188 (GB); Dalsland: Ödskölt, S of lake Ivägsjön, on deciduous wood, 22 September 1990, K. Hjortstam 17197 (K.-H. Larsson private collection).

NORWAY. Nord-Tröndelag: Snåsa, Bergsåsen, boreal, deciduous forest on soil with intermediate pH, 28 August 2012, K.-H. Larsson (holotype: O F110306!, GenBank Acc. No. ITS: MK290692).

SH030566.07FU

The name refers to the overall similarity between this species and P. tristis.

Basidiome annual, resupinate, membranaceous, effused to approximately ten centimetres in diameter. Mature parts continuous, with a rather firm, fibrous and compact, yet quite soft and elastic texture. Hymenium smooth; brown with a reddish hue. Immature parts discontinuous, byssoid with a cottony texture. Subhymenium and hymenium of immature parts initially pale greyish-blue, when more mature dark blue grey. Subiculum well-developed, loose, fibrous, brown with an orange hue; forms the outer edge of the basidiome, extending noticeably beyond the hymenium. All characters recorded in dried state.

Figure 17. 

Micromorphological features of P. tristoides in KOH. Holotype: A, B, C basidiospores in frontal face D, E in lateral face E subicular hyphae.

Hyphal cords lacking, but loose bundles of subicular hyphae sometimes present.

Hyphal system monomitic, clamp connections absent from all hyphae.

Subicular hyphae noticeably long and straight, thick-walled; forming a loose tissue. Individual hyphae (4.7–) 4.9–7.1 (–7.6) μm wide, with a mean width of 6.0 μm; orange brown to dark brown in KOH, orange brown to brown in water.

Subhymenial hyphae often somewhat sinuous, thin to thick-walled; forming a rather dense tissue. Individual hyphae (3.1–) 3.2–5.3 (–5.4) μm wide, with a mean width of 4.6 μm; pale yellowish-brown in KOH, pale green to blue green in the presence of air; pale green to pale orange green in water, with strongly granular contents.

Encrustation granular, amyloid, concolourous with the hyphae in both KOH and water; scattered in occurrence on the upper parts of subhymenial hyphae and on the lower parts of basidia.

Basidia with four slightly curved sterigmata, occasionally two-sterigmate; clavate to narrowly clavate, sometimes clavopedunculate, thin-walled, with one-three slight constrictions. Dimensions: (49–) 54–72 (–75) × (7.3–) 7.9–10.0 (–10.5) μm; mean dimensions: 63 × 9.1 μm. Sterigmata (7.6–) 7.8–9.9 (–10.5) μm long, with a mean length of 8.6 μm. Colours and reactions the same as for the subhymenial hyphae.

Cystidial organs lacking.

Basidiospores in frontal face generally with a subcircular basic shape and an angular to nodulose or sometimes cross-shaped outline, covered in bi- or trifurcate, sometimes singularly attached, echinuli. A majority of the spores with three-five indistinct corners to distinct, square lobes; subellipsoid, ovoid and subcircular spores with a rather evenly rounded outline occasionally occurring, as well as subcircular, six-lobed spores; abnormally large spores originating from two-sterigmate basidia infrequently seen. Frontal dimensions: 7.7–8.6 (–8.8) × (7.4–) 7.7–9.3 (–9.5) μm; mean dimensions: 8.2 × 8.5 μm; Q-value: 0.9–1.1; mean Q-value: 1.0. Echinuli (0.5–) 0.7–0.9 (–1.1) μm long, with a mean length of 0.8 μm. Lateral face ellipsoid, usually with evenly rounded edges, sometimes with one-three lobes. Lateral dimensions: (7.9–) 8.0–8.6 × 6.0–6.5 (–6.7) μm; mean dimensions: 8.2 × 6.3 μm; Q-value: 1.2–1.4; mean Q-value: 1.3. Colour in KOH brown to yellow brown, in the presence of air often with a green to blue green reaction; in water pale greenish to pale greenish-orange; occasionally amyloid.

Chlamydospores lacking.

The only specimen recorded to date of P. tristoides is the type collection, which was obtained in an old, mixed forest on soil with intermediate pH. UNITE sequence metadata show that the species forms ectomycorrhiza with at least Populus alba and Cephalanthera damasonium (Kõljalg et al. 2005, Nilsson et al. 2019).

Basidiomata encountered in: Norway. Soil or root tip samples confirm presence also in: Estonia and the Czech Republic.

Within the P. tristis group, the basidiome of P. tristoides can be recognised by its lack of hyphal cords and skeletal hyphae and its soft, yet rather firm and compact and ± elastic texture after drying, bluish to greenish colour of immature parts, wide subicular hyphae, medium sized, angular-nodulose spores and relatively short echinuli and sterigmata. Pseudotomentella tristis is similar but has longer echinuli and sterigmata, P. sciastra has smaller, star-shaped spores and H. rhacodium (only known from the type) has hard, brittle basidiomata after drying.

Thelephora umbrina Fr. Elench. fung. 1: 199 (1828), non Pers. (1801), sanctioned name [Fries explicitly excluded T. umbrina Pers. from his concept]. Hypochnus umbrinus (Fr.) Fr. [basionym not cited], Summa veg. Scand.: 337 (1849), non Wallr. (1833), illegitimate name [combination also made by Quélet (1888) and Burt (1916)]. Corticium umbrinum (Fr.) Fr., Hymenomyc. eur.: 658 (1874). Coniophora umbrina (Fr.) Sacc., Syll. fung. 6: 652 (1888) [as (Alb. & Schwein.) Fr.]. Tomentella umbrina (Fr.) Litsch., Bull. Soc. Mycol. France. 49(1): 52 (June 20, 1933) [combination also made by Donk, Meded. Bot. Mus. Herb. Rijks Univ. Utrecht. 9: 29 (before July 7 1933)]. Prillieuxia umbrina (Fr.) Park.-Rhodes 1956 Ann. Bot. (Oxford). 20(78): 258. 1956, invalid name, basionym not cited. Tomentellastrum umbrinum (Fr.) Svrček, Ceská Mykol. 12(2): 70 (1958).

SWEDEN. Småland: Femsjö, E. Fries (neotype: Herb. Fries [UPS F003106]!, designated by E.A. Burt in Ann. Missouri Bot. Gard 3: 213 (1916)); Småland: Hylte, Femsjö, Femsjö Church Nature Reserve, boreonemoral, mixed forest on soil with intermediate pH, 7 September 2016, S. Svantesson 351 (EPITYPE: GB!, here designated, MycoBank Typification No. MBT384818, GenBank Acc. No. ITS: MK290700).

SH030549.07FU

Basidiomata annual, resupinate, membranaceous, effused – often to several tens of centimetres in diameter. Mature parts continuous, with a cottony texture when fresh and a rather firm, fibrous and compact, yet quite soft and elastic texture when dried. Hymenium smooth, but sometimes strongly undulating; blue grey or purplish-grey to pale brown or brown when fresh, pale brown to brown when dried, sometimes with a reddish or greyish hue. Immature parts discontinuous, byssoid with a cottony texture, both when fresh and when dried. Subhymenium and hymenium of immature parts pale blue grey or pale purplish-grey to pale brown when fresh, pale brown when dried. Subiculum well developed, loose, fibrous, orange brown; often forms the outer edge of basidiomata, extending noticeably beyond the hymenium.

Figure 18. 

Morphological features of P. umbrina, mounted in KOH and macroscopically. A (O F110268) B (epitype) C (epitype) basidiospores in frontal face D, E in lateral face (epitype) F subicular hyphae (epitype) G (epitype) H (SS174) mature basidiomata.

Hyphal cords lacking, but loose bundles of subicular hyphae sometimes present.

Hyphal system monomitic, clamp connections and reaction in Melzer’s reagent absent from all hyphae.

Subicular hyphae noticeably long and straight, thick-walled; forming a loose tissue. Individual hyphae 3.3–4.8 (–5.3) μm wide, with a mean width of 4.0–4.3 μm; orange brown to brown in KOH, orange brown in water.

Subhymenial hyphae often somewhat sinuous, thin to thick-walled; forming a rather dense tissue. Individual hyphae (2.8–) 2.9–5.0 (–5.9) μm wide, with a mean width of 3.7–4.2 μm; in the upper parts, pale green in KOH, sometimes with a faintly blue or brown hue; in the lower parts, orange brown to brown; in water, orange brown, with strongly granular contents.

Encrustation lacking.

Basidia with four slightly curved sterigmata, occasionally two-sterigmate; clavate to narrowly clavate, sometimes clavopedunculate, thin-walled, with one-three slight constrictions. Dimensions: (54–) 57–71 (–77) × (8.3–) 8.5–10.9 (–12.4) μm; mean dimensions: 60–64 × 9.5–10.3 μm. Sterigmata (8.7–) 8.8–11.1 (–11.7) μm long, with a mean length of 9.6–10.5 μm. Colour for the great majority very pale green in KOH, sometimes with a faintly blue or brown hue (but not the blue green reaction present in other species), for a small number formed directly from subicular hyphae brown; sometimes with granular contents; in water orange brown and with strongly granular contents.

Cystidial organs lacking.

Basidiospores in frontal face generally with a broadly subellipsoid, triangular or subcircular basic shape and an unlobed, angular, nodulose or sometimes cross-shaped outline, covered in bi- or trifurcate, occasionally singularly attached, echinuli. A majority of the spores normally with three-six indistinct corners to distinct, square lobes; broadly ellipsoid, unlobed spores infrequently occurring (but dominate in some collections), as well as abnormally large spores originating from two-sterigmate basidia. Frontal dimensions: 7.7–9.3 (–9.4) × (7.6–) 7.9–9.1 (–9.4) μm; mean dimensions: 8.3–8.7 × 8.4–8.7 μm; Q-value: (0.9–) 1.0–1.1; mean Q-value: 1.0. Echinuli (0.7–) 0.8–1.5 μm long, with a mean length of 1.1–1.2 μm. Lateral face ellipsoid to narrowly ovoid or sometimes semicircular in shape, usually with evenly rounded edges, sometimes with one-three lobes. Lateral dimensions: 8.0–9.3 (–9.6) × (5.1–) 5.6–6.7 (–6.9) μm; mean dimensions: 8.4–8.7 × 6.0–6.1 μm; Q-value: (1.2–) 1.3–1.6 (–1.7); mean Q-value: 1.4–1.5. Colour in KOH pale green to pale brown; in water orange brown to brown; inamyloid.

Chlamydospores lacking.

P. umbrina has a wide ecological amplitude. Recent Scandinavian collections have been made in young to old deciduous, mixed and coniferous forests on soil with low to high pH, as well as on the tundra. The species has been found to form ectomycorrhiza with at least Abies alba, Alnus rubra, Betula nana, Betula pubescens ssp. czerepanovii, Betula pubescens ssp. pubescens, Dryas octopetala, Fagus sylvatica, Picea abies, Picea glauca, Picea mariana, Pinus banksiana, Pinus pinaster, Pinus sylvestris, Pseudotsuga menziesii, Pyrola media, Quercus petraea, Salix polaris and Tsuga canadensis (collection data; Kõljalg et al. 2005, Nilsson et al. 2019).

Basidiomata encountered in: Canada, Estonia, Finland, Norway, Sweden and the United Kingdom. Soil or root tip samples confirm presence also in: France, Poland, Spain and the United States.

The nomenclatural situation surrounding P. umbrina is complex. Fries described Thelephora umbrina, explicitly excluding Thelephora umbrina Pers., but synonymising it with Thelephora umbrina var. lignatilis Alb & Schwein. These names might represent different species or not, but in either case do not threaten Thelephora umbrina Fr., due to the sanctioning.

A large number of names synonymous with P. umbrina have been illegitimately or superfluously published. Fries himself (1847), as well as Quélet (1888) and Burt (1916), seem to have overlooked Wallroth’s (1833) combination of Hypochnus umbrinus (Alb. & Schwein.) Wallr. from Himantia umbrina Alb. & Schwein, (1805) and hence created illegitimate name combinations. The status of Donk’s (1933) combination of Tomentella umbrina (Fr.) Donk versus Litschauer’s (1933) remains hard to evaluate due to the fact that, although 20 June is known to be the date of Litschauer’s publication, 7 Julyis when Donk defended the thesis wherein he published his combination; the publication date of Donk’s thesis was probably at an unknown point in time prior to that of his dissertation. Combinations based on Thelephora umbrina where the combining authors cite Alb. & Schwein as authors of the basionym (e.g. Saccardo 1888) have to be considered miscitations, since there is no Thelephora umbrina Alb. & Schwein.

Our interpretation of Thelephora umbrina Fr. as the basionym follows Burt (1916), Litschauer (1933), Svrcek (1958) and Larsen (1967), although Rogers and Jackson (1943) considered it to be a synonym of Coniophora olivacea. The name is not used here in the sense of what we today interpret as C. olivacea, but in the sense of Burt’s (1916) type selection.

The material in the Fries Herbarium cited by Burt (1916), as the type of Thelephora umbrina Fr., constitutes a collection made by Fries at locus classicus, Femsjö, but in Fries’s own handwriting, it is identified as Corticium umbrinum (Fr.) Fr., a name he combined T. umbrina to in 1874 (Fries 1874). Therefore, Burt’s typification cannot be considered a lectotype, but must be regarded as a neotype. We here designate an epitype from Femsjö, which matches the neotype morphologically.

Within the P. tristis group, basidiomata of P. umbrina can be recognised by their brown colour – blue or green colours are completely absent from immature parts and from the subhymenium of mature parts – their soft, rather elastic texture after drying and their microcharacters. Pseudotomentella umbrinascens is very similar but has slightly different microcharacters (see key). Hypochnus rhacodium (only known from the type) is also similar but has hard, brittle basidiomata after drying.

CANADA. Newfoundland: Crooked Knife, mixed forest with Betula, Alnus and Picea, 99 m a.s.l., 10 September 2008, U. Kõljalg (TU 108084*);

ESTONIA. Põlva: Vastse-Kuuste, older Pinus-Picea mixed forest between Kiidjärve and Taevaskoja, near Maarja village, 22 September 2005, U. Kõljalg (TU 100329, 100339, 100340); Saare: Muhu, Kesselaid, Karjalasma forest, Picea abies forest, 28 August 1998, Erast Parmasto (TAAM 174051); Põlva: Vastse-Kuuste, coniferous forest with Pinus and Picea along road between Kiidjärve and Taevaskoja, east of Ahja river, 18 August 2005, U. Kõljalg (TU 100194); Viljandi: Pääsmä laas, Sooma National Park, on a fallen Betula trunk over Halliste river, 7 September 2000, U. Kõljalg (TU 108538);

FINLAND. Kanta-Häme: Lammi, Kotinen Virgin Forest, 10 September 2001, U. Kõljalg (TU 108742, 108743, 108744); Etelä-Häme, Ruovesi, Siikaneva swamp islands, 14 September 1999, U. Kõljalg (TAAM 159809, 159810); Satakunta: Ilkaalinen, under Picea log and mosses, 29 August 2010, U. Kõljalg (TU 115017); Varsinais-Suomi: Parainen, Kuggö, 24 October 2009, P. Kunttu (TU115344*);

NORWAY. Oppland, Dovre, Hjerkinn, low alpine vegetation under Salix phyllicifolia, Salix lapponica and Betula nana, on soil with low pH, 14 September 2014, S. Svantesson 216, 221* (GB); Akershus: Asker, Skaugumåsen, boreonemoral, mixed forest on moderately alkaline, moderately nutrient-rich ground under, 23 September 2010, S. Svantesson (O F110268*); Troms: Kvænangen, Kvænangselva, boreal mixed forest on soil with low pH, 31 August 2013, B. Larsson and K.-H. Larsson (O F110269); Ibidem, boreal, deciduous forest on soil with intermediate pH, 31 August 2013, B. Larsson and K.-H. Larsson (O F110270, F110271); Oppland: Dombås, Hjerkinnholen, boreal, mixed forest on soil with low pH, 30 September 2013, K.-H. Larsson (O F110272, F110273, F110274, F110275, F110276, F110277); Sogn og Fjordane: Leikanger, Flætene-Vesterheim, boreonemoral, mixed forest on soil with low pH, 2 October 2012, K.-H. Larsson and S. Svantesson (O F110278, F110279, F110280); Sogn og Fjordane: Eid, Eitrefjellet, deciduous forest on soil with high pH, 25 September 2013, K.-H. Larsson (O F110281); Oppland, Dovre, Grimsdalen, Storberget, subalpine Betula pubescens ssp. czerepanovii forest on soil with low pH, 26 August 2010, K.-H. Larsson and S. Svantesson (O F110282, F110283, F110284, F110285, F110286); Aust-Agder: Tvedestrand, Eidbo, boreonemoral, mixed forest on soil with intermediate pH, 10 September 2010, S. Svantesson and N. Svensson (O F110307); Aust-Agder: Åmli, Gangsei W, boreonemoral, mixed forest on soil with low pH, 09 September 2010, S. Svantesson and N. Svensson (O F110308); Telemark: Drangedal, Asgjerdstigfjellet, boreonemoral, deciduous forest on on soil with intermediate pH, 28 September 2010, S. Svantesson and N. Svensson (O F110309, F110310); Vest-Agder: Mandal, Uføra, nemoral, deciduous forest on soil with high pH, 26 September 2012, K.-H. Larsson and S. Svantesson (O F110287); Sogn og Fjordane: Leikanger, Kvinnafossen, boreonemoral, mixed forest on soil with high pH, 2 October 2012, K.-H. Larsson and S. Svantesson (O F110288); Nord-Tröndelag: Grong, Gartlandselva, boreal, coniferous forest on soil with low pH, 27 August 2012, K.-H. Larsson (O F110289, F110290, F110291, F110292, F110293, F110294); Nordland: Saltdal, Nystadneslia, boreal, mixed forest on soil with intermediate pH, 24 August 2012, K.-H. Larsson (O F110295, F110296*); Telemark: Tokke, Dalen, Huvestad, boreonemoral, mixed forest on soil with high pH, 28 September 2010, S. Svantesson and N. Svensson (O F110311); Akershus: Nannestad, Tomte farm, 3 September 2004, U. Kõljalg (TU 100005, 100007); Telemark: Sauherad, E of Nordagutu, W slope of Bjørndalsfjell along path to Svanastøl, 24 September 2003, K.-H. Larsson 12094 (TU); Buskerud: Nes, Alungruken, 25 September 1997, J. Stokland (TU 115209*), Rogaland: Forsand, Rössdalen, on Salix sp., 14 October 1998, K. Hjortstam 17918 (K.-H. Larsson private collection);

SWEDEN. Lycksele Lappmark: Storuman, Blaiken N, boreal, mixed, old-growth forest on fertile, moderately alkaline ground, 26 August 2015, S. Svantesson 137 (GB); Västerbotten: Umeå, Stora Tuvan, older, boreal, mixed forest on soil with low pH, 28 August 2015, S. Svantesson 174*, 175 (GB); Lule Lappmark: Gällivare, Ritsem, subalpine Betula pubescens ssp. czerepanovii forest on soil with low pH, 11 August 2016, S. Svantesson 234, 239*, 240 (GB); Lule Lappmark: Jokkmokk, Slappejaure NO, middle alpine vegetation on soil with high pH, 14 August 2016, S. Svantesson 255, 256 (GB); Lule Lappmark: Jokkmokk, Unna Duvgge, low alpine vegetation on soil with intermediate pH, 15 August 2016, S. Svantesson 277 (GB); Lule Lappmark: Jokkmokk, Ajajaure N, low alpine vegetation on soil with high pH, 16 August 2016, S. Svantesson 279, 280* (GB); Halland: Kungsbacka, Släp, Särö Västerskog, old growth Pinus and Quercus forest, under a Pinus log, 1 October 1999 U. Kõljalg (TAAM 159818); Ångermanland; Sollefteå, Sörgraninge mångfaldspark, Språngsjöberget, 9 September 2014, K.-H. Larsson 16608 (GB); Västergötland: Alingsås, Simmenäshalvön, Gräskärr, on Picea, 5 October 2008, B. and K. Hjortstam 20311, 20332 (K.-H. Larsson private collection); Ibidem, on wood of Quercus on the ground, 13 September 2004, K. Hjortstam 18795 (K.-H. Larsson private collection); Ibidem, on Picea bark, 17 October 2001, K. Hjortstam 18531 (K.-H. Larsson private collection); Västergötland: Vårgårda, Nårunga, Sandviksås, on branch of Quercus robur, 8 November 2000, Björn Nordén (TU 115240);) ; Öland: Böda, Fagerör, under log of Pinus sylvestris, 15 October 2016, E. Larsson 387-16 (GB); Öland: Böda, Bryum Sandvik, under log of Pinus sylvestris, 15 October 2016, E. Larsson 384B-16 (GB);

UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND. Scotland, Invernesshire: Glen Strathfarrar National Nature Reserve, ancient Pinus sylvestris forest with a few oak trees, 14 September 2005, U. Kõljalg (TU 100304); Scotland, Morayshire: Culbin Forest, planted Pinus sylvestris forest on sand dunes, 13 September 2005, U. Kõljalg (TU 100292).

SWEDEN. Bohuslän: Tanum (municipality), Tanum (parish), Greby Kleva, boreonemoral, deciduous forest on soil with high pH, RT90: E1236840, N6518916, 6 September 2016, S. Svantesson 335 (holotype: GB!, GenBank Acc. No. ITS: MK290697)

SH030563.07FU

The name refers to the overall morphological similarity to P. umbrina.

Basidiome annual, resupinate, membranaceous, effused to approximately ten centimetres in diameter. Mature parts continuous, with a cottony texture when fresh and a rather firm, fibrous and compact, yet quite soft and elastic texture when dried. Hymenium smooth; greenish-brown when fresh, pale brown when dried. Immature parts discontinuous, byssoid with a cottony texture, both when fresh and when dried. Subhymenium and hymenium of the immature parts initially yellowish-white to pale brown, in the dried basidiome, when more mature pale brown. Subiculum well developed, loose, fibrous, pale yellowish-brown to pale orange brown; forms the outer edge of the basidiome, extending noticeably beyond the hymenium.

Figure 19. 

Micromorphological features of P. umbrinascens in KOH. Holotype: A, B, C basidiospores in frontal face D, E in lateral face E subicular hyphae.

Hyphal cords lacking, but loose bundles of subicular hyphae sometimes present.

Hyphal system monomitic, clamp connections and reaction in Melzer’s reagent absent from all hyphae.

Subicular hyphae noticeably long and straight, thick-walled; forming a loose tissue. Individual hyphae 3.1–) 3.2–4.3 (–4.8) μm wide, with a mean width of 3.7 μm; pale orange brown to brown in KOH, orange brown in water.

Subhymenial hyphae often somewhat sinuous, thin to thick-walled; forming a rather dense tissue. Individual hyphae 3.6–5.7 (–7.1) μm wide, with a mean width of 4.5 μm; pale grey brown to grey brown or brown in KOH; orange brown to pale green in water (but not with the blue green reaction present in other species), with strongly granular contents.

Encrustation not seen.

Basidia with four slightly curved sterigmata, occasionally two-sterigmate; clavate to narrowly clavate, sometimes clavopedunculate, thin-walled, with one-three slight constrictions. Dimensions: (57–) 58–71 (–75) × (8.8–) 9.5–11.5 (–12.5) μm; mean dimensions: 64 × 10.6 μm. Sterigmata 8.1–9.5 (–10.1) μm long, with a mean length of 8.6 μm. Colours and reactions the same as for the subhymenial hyphae, but in addition sometimes with granular contents in KOH.

Cystidial organs lacking.

Basidiospores in frontal face generally with a triangular or subcircular basic shape and an angular to cross-shaped or sometimes nodulose outline, covered in bi- or trifurcate, sometimes singularly attached, echinuli. Nearly all spores with three-four distinct, often rounded lobes; subcircular, five-lobed spores infrequently occurring, as well as abnormally large spores originating from two-sterigmate basidia. Frontal dimensions: (8.5–) 8.7–9.4 (–9.6) × (8.4–) 8.7–9.2 (–9.3) μm; mean dimensions: 8.9 × 8.9 μm; Q-value: 1.0 (–1.1); mean Q-value: 1.0. Echinuli (0.9–) 1.0–1.9 (–2.0) μm long, with a mean length of 1.6 μm. Lateral face ellipsoid to narrowly ovoid or sometimes semicircular in shape, usually with evenly rounded edges, sometimes with one-three lobes. Lateral dimensions: 8.5–9.2 (–9.4) × (5.7–) 6.0–6.5 μm; mean dimensions: 8.9 × 6.2 μm; Q-value: 1.3–1.5 (–1.6); mean Q-value: 1.4. Colour in KOH pale brown to pale greenish-brown colour; in water pale brownish-orange to pale greenish-orange; inamyloid.

Chlamydospores lacking.

The only specimen recorded to date of P. umbrinascens is the type collection, which was obtained in an old, coastal, deciduous forest on soil with high pH. UNITE sequence metadata shows that the species forms ectomycorrhiza with at least Corylus avellana (Kõljalg et al. 2005, Nilsson et al. 2019).

Basidiomata encountered in: Sweden. Soil or root tip samples confirm presence also in: Italy.

Within the P. tristis group, basidiomata of P. umbrinascens can be recognised by their brown colour, their soft, rather elastic texture after drying and their microcharacters. Blue or green colours are completely absent from immature parts and from the subhymenium of mature parts. Pseudotomentella umbrina is very similar but has slightly different microcharacters (see key). Hypochnus rhacodium (only known from the type) is also similar but has basidiomata that are hard and brittle after drying.

UNITED STATES. Washington: Olympic Peninsula, Sol Duc River, on coniferous wood, 25 August 1957, J. L. Lowe 8061 (holotype: BPI US0291345!; isotype: SYRF).

Basidiome annual, resupinate, membranaceous, effused to approximately ten centimetres in diameter. Mature parts continuous, with a cottony to rather firm, fibrous and compact, yet quite soft and elastic texture. Hymenium smooth; bluish-grey to brownish-grey. Immature parts discontinuous, byssoid with a cottony texture. Subhymenium and hymenium of immature parts bluish-grey. Subiculum well-developed, loose, fibrous, orange brown; forms the outer edge of the basidiome, extending noticeably beyond the hymenium. All characters recorded in dried state.

Figure 20. 

Micromorphological features of P. longisterigmata in KOH. Holotype: A, B, C basidiospores in frontal face D in lateral face E basidia F subicular hyphae.

Hyphal cords lacking, but loose bundles of subicular hyphae sometimes present.

Hyphal system monomitic, clamp connections absent from all hyphae.

Subicular hyphae noticeably long and straight, thick-walled; forming a loose tissue. Individual hyphae 4.9–7.2 μm wide, with a mean width of 6.2 μm; orange brown to brown in KOH, orange to orange brown in water.

Subhymenial hyphae often somewhat sinuous, thin to thick-walled; forming a rather dense tissue. Individual hyphae (3.0–) 3.2–4.9 (–6.1) μm wide, with a mean width of 3.9 μm; pale brownish-green in KOH, blue green in the presence of air; brownish-green in water, with strongly granular contents.

Encrustation granular, probably amyloid (hard to observe due to the colour); dark brownish-green in KOH, dark blue green in the presence of air; blackish in water; scattered in occurrence on the upper parts of subhymenial hyphae and on the lower parts of basidia.

Basidia with four very long, slightly curved to hypha-like sterigmata, occasionally two-sterigmate; clavate or sometimes clavopedunculate, thin-walled, with one-three slight constrictions. Dimensions: (73–) 77–110 (–121) × (12.3–) 13.0–15.1 (–16.3) μm; mean dimensions: 91 × 13.9 μm. Sterigmata (11.2–) 11.7–17.9 (–19.3) μm long, with a mean length of 14.7 μm. Colours and reactions the same as for the subhymenial hyphae, but in addition often with granular contents in KOH.

Cystidial organs lacking.

Basidiospores in frontal face generally with a subcircular basic shape and an angular to nodulose or sometimes cross-shaped outline, covered in bi- or trifurcate, sometimes singularly attached, echinuli. A majority of the spores with three-five indistinct lobes; unlobed subellipsoid or broadly ovoid spores present to a lesser extent, as well as subcircular, six or seven-lobed spores; abnormally large spores originating from two-sterigmate basidia infrequently occurring. Frontal dimensions: (9.7–) 10.0–11.7 × (9.4–) 9.8–11.7 μm; mean dimensions: 11.0 × 10.7 μm; Q-value: (0.9–) 1.0 (–1.1); mean Q-value: 1.0. Echinuli 1.2–1.8 (–2.1) μm long, with a mean length of 1.5 μm. Lateral face ellipsoid to ovoid, usually with evenly rounded edges, sometimes with one-three lobes. Lateral dimensions: 10.3–11.5 (–11.7) × (6.7–) 7.5–9.1 μm; mean dimensions: 10.9 × 8.5 μm; Q-value: 1.2–1.6; mean Q-value: 1.3. Colour in KOH pale brown to pale greenish-brown, in the presence of air often with a green to blue green reaction; in water brown; occasionally amyloid.

Chlamydospores lacking.

The only specimen of P. longisterigmata recorded to date is the type collection, which was collected on coniferous wood in a coastal forest in the state of Washington, United States.

Basidiomata encountered in: the United States.

The type collection is large and in seemingly good condition but repeated attempts at obtaining a useful DNA sequence from it proved unfruitful. The specimen exhibits a peculiar morphology, where the basidia carry sterigmata that are unusually long for the P. tristis group. They are often cylindrical rather than tapering and hence resemble generative hyphae – a growth form that basidia are sometimes seen reverting into in corticioid basidiomata formed under unfavourable conditions. It is therefore doubtful whether P. longisterigmata is a true species, but since this presently cannot be ascertained and, in order to stimulate its recollection, the name is here retained as a separate species.

There are relatively few spores in the hymenium of the holotype and many of them are immature. A more mature fruiting body of the species would hence probably have a browner colour.

Within the P. tristis group, the basidiome of P. longisterigmata can be recognised by its lack of hyphal cords and skeletal hyphae, its soft, yet rather firm and compact and ± elastic texture after drying, bluish to greenish colour of immature parts, wide subicular hyphae, large spores and long sterigmata. Pseudotomentella alobata, P. pluriloba and P. abundiloba are similar but all have smaller spores and shorter sterigmata.

UNITED STATES OF AMERICA. Pennsylvania: on underside of decaying logs of apparently a frondose species, E. Michener 1435 (syntypes: Mo. Bot. Gard. Herb. 5095 [BPI US0291002]!; FH Curtis Herb. 4061; K Curtis Herb. 4061, designated by E.A. Burt in Ann. Missouri Bot. Gard. 13: 322 (1926)).

Basidiome annual, resupinate, membranaceous, effused. Mature parts continuous, with a hard and rather brittle texture. Hymenium smooth; pale brown to brown with a pink hue. Subiculum loose, fibrous and dark brown with an orange hue. All characters recorded in dried state.

Figure 21. 

Micromorphological features of H. rhacodium in KOH. Syntype: A, B basidiospores in frontal face C, D in lateral face E subicular hyphae with granulation and F without.

Hyphal cords lacking, but loose bundles of subicular hyphae sometimes present.

Hyphal system monomitic, clamp connections and reaction in Melzer’s reagent absent from all hyphae.

Subicular hyphae noticeably long and straight, thick-walled; forming a loose tissue. Individual hyphae (5.6–) 5.7–7.3 (–8.0) μm wide, with a mean width of 6.5 μm; pale to dark orange brown in both KOH and water, sometimes with granular contents which turn blue green in the presence of air.

Subhymenial hyphae often somewhat sinuous, thin to thick-walled; forming a rather dense tissue. Individual hyphae (3.7–) 3.8–5.3 (–6.1) μm wide, with a mean width of 4.7 μm; brown to pale orange brown or pale green in KOH (but not with the blue green reaction present in other species); orange brown to brown in water, with strongly granular contents.

Encrustation granular, probably amyloid (hard to observe due to the colour); brownish-black in KOH, dark blue green in the presence of air; brownish-black in water; scattered in occurrence on the subicular hyphae.

Basidia with four slightly curved sterigmata, occasionally two-sterigmate; narrowly clavate or sometimes narrowly clavopedunculate, thin-walled, with one-three slight constrictions. Dimensions: 73–105 (–109) × (8.8–) 8.9–10.1 (–11.2) μm; mean dimensions: 94 × 9.6 μm. Sterigmata (8.5–) 9.5–12.1 (–12.5) μm long, with a mean length of 10.9 μm. Colours and reactions the same as for the subhymenial hyphae.

Cystidial organs lacking.

Basidiospores in frontal face generally with a subcircular basic shape and an angular to nodulose or sometimes cross-shaped outline, covered in bi- or trifurcate, sometimes singularly attached, echinuli. Nearly all spores with three-five distinct, rounded to square lobes; abnormally large spores originating from two-sterigmate basidia infrequently occurring. Frontal dimensions: (7.8–) 8.0–9.1 (–9.3) × (7.7–) 7.8–8.9 (–9.0) μm; mean dimensions: 8.3 × 8.3 μm; Q-value: 0.9–1.1; mean Q-value: 1.0. Echinuli (0.9–) 1.0–1.6 (–1.7) μm long, with a mean length of 1.3 μm. Lateral face ellipsoid to ovoid or sometimes subcylindrical, usually with angular edges, sometimes with one-three lobes. Lateral dimensions: (7.9–) 8.2–8.9 × (5.4–) 5.9–6.8 (–7.0) μm; mean dimensions: 8.5 × 6.3 μm; Q-value: 1.2–1.4 (–1.6); mean Q-value: 1.3. Colour in KOH brown to orange brown, in the presence of air with a blue green reaction; in water greenish-orange to orange brown; inamyloid.

Chlamydospores lacking.

The only specimen of H. rhacodium recorded to date is the type collection, which was collected in Pennsylvania, United States. No further information on habitat or any further locality description is available.

Basidiome encountered in: the United States.

The hymenium of H. rhacodium is very thick and dense in comparison to all other Pseudotomentella species. It consists of tightly packed basidia, which are overlapping in length and have a total thickness equalling four-six basidial lengths. All other morphological characters fit well within the P. tristis group, thus suggesting an abnormal basidiome.

Within the P. tristis group, the basidiome of H. rhacodium can be recognised by its lack of hyphal cords and skeletal hyphae and its hard and brittle texture after drying. This feature makes it unique within the group and the risk for confusion with any other described species should hence be small.

Thelephora arachnoidea Berk. & Broome, J. Linn. Soc., Bot. 14: 64 (1873) [1875]. Hypochnus arachnoideus (Berk. & Broome) Bres., Ann. Mycol. 1(2): 108 (1903). Tomentella arachnoidea (Berk. & Broome) Höhn. & Litsch., Wiesner Festschrift: 77 (1908).

CEYLON [Nowadays Sri Lanka]. Habgalla, Feb. 1868, [M. J. Berkeley and C. E. Broome] No. 539 (K).

Bresadola (1916) combined Thelephora arachnoidea Berk. & Broome to Septobasidium, and the species was accepted by Couch (1938) in his detailed review of the genus. We thus have no reason to believe that this species belongs in Pseudotomentella.

Auricularia phylacteris Bull., Herb. France 10: plate 436, fig. 2 (1790). Thelephora phylacteris (Bull.) J.F.Gmel., Syst. nat. 2 (2): 1441 (1792) [combination also made by de Candolle (1815)]. Thelephora biennis, Fr., Syst. mycol. 1: 449 (1821), sanctioned name. Phylacteria biennis (Fr.) Bigeard, Fl. champ. sup. France 2: 452 (1913).

Bulliard JBF (1790) Herbier de la France, ou Collection complette des plantes indigenes de ce royaume; Avec leurs Détails Anatomiques, leurs propriétés, et leurs usages en Medecine. Tome 10, plate 436, figure 2, LECTOTYPE of Auricularia phylacteris, here designated (Mycobank Typification No. MBT384912), LECTOTYPE of Thelephora biennis, here designated (MBT384913).

Bulliard (1790) described Auricularia phylacteris and Gmelin (1792) combined it to Thelephora. Seemingly, both Fries and de Candolle (1815) overlooked Gmelin’s combination. Fries (1821) created the name Thelephora biennis, citing under it A. phylacteris and T. phylacteris DC, but seems to attribute it to de Candolle in the index of the Systema Mycologicum 3 (Fries 1832). This is probably an error and since Fries is the original author of the name, we agree with Petersen (1975) that the authorship is Thelephora biennis Fr.

Fries (1821) indicated “v.ic.”, which would be a reference to the plate in Bulliard (1790). There are no specimens under any of the aforementioned names known to have been examined by Bulliard, de Candolle or Fries. Consequently Bulliard’s plate of A. phylacteris (1790), mentioned by Fries (1821), is here designated as the lectotype of A. phylacteris and T. biennis.

The protologue of T. biennis describes and the plate of A. phylacteris depicts a species which is plicated at the lower part of the basidiome, yellowish-white when young, brown when older and which eventually turns black. It is further described as biennial and growing up from the ground and on to stones and branches, if they are present in its vicinity. It is hence doubtful whether the species in question belongs to the Thelephorales at all and, even though it has been synonymised with P. umbrina by Burt (1916), Litschauer (1933) and Svrček (1958), it does not match any Pseudotomentella described to date.