Pseudohydnum-orbiculare used to be ID'abel compared to the pseudohydnum-totarae. I'm unsure of how, but suspect enviroment / substrate / size / macro structure would be used. However since Pseudohydnum viridimontanum has been found in NZ in 2025, this indicates that micro work is required.
Pseudohydnum orbiculare J.A. Cooper, Type—New Zealand. South Island, West Coast Region, Ship Creek, Haast, on an unidentified rotten branch,
Etymology—Orbiculare (Lat.): refers to the species having orbicular basidiomata.
Diagnosis—Differs from other Pseudohydnum species by pileate basidiomata without a well-formed pseudostipe, orbicular pilei, dark-gray to black pileal surface when fresh, hymenophore with sparse spines (0.5–1 per mm at base), growth mostly on angiosperm, and distribution so far restricted to New Zealand.
Basidiomata—Annual, gelatinous when fresh, pileate, not confluent, in grouped tiers. Pilei laterally attached, with a narrow point of attachment, orbicular to dimidiate, up to 50 mm diam., pileal surface white to grayish brown (7E3–9E3) to reddish brown (11E5), smooth to minutely velutinate, with scattered, bluntly conical spines up to 0.2 mm long. Hymenophore white to pale-brown (8B2). Hymenophore spines white, conical, gelatinous, 2–4 mm long, and 1–2 mm wide at the base, 0.5–1 per mm at base. Context 0.5–1.5 mm thick, concolorous with pileal surface.
Hyphal structure—Monomitic; generative hyphae with clamp connections. Contex-tual and spine tramal hyphae hyaline, thin- to slightly thick-walled, frequently branched, agglutinate,1.5–9 µm in diam. Basidia longitudinally cruciate-septate, 10–14 × 10 µm, with four sterigmata up to 10 × 2 µm. Probasidia lageniform to clavate with stalks 1.5–2 µm in diam. Hyphidia irregular, mostly unbranched, slightly swollen towards apex, clamped at the base. Basidiospores (excluding apiculus) broadly ellipsoid to subglobose, hyaline, thin- walled, occasionally with a guttule, germinating by repetition, 6.5–7.9 × 5.6–6.8 µm,
Distribution—Distributed throughout New Zealand but perhaps more common in the south.
Habitat—The species is commonly associated with angiosperm hosts, including southern beech (Nothofagaceae), but several collections were obtained from rotten trunks of Pinus Radiata
Figure 3. Basidiomata and microscopic structures of Pseudohydnum orbiculare. (A) Basidiomata (holo- otype PDD 112653). (B) Basidiomata (PDD 112654). (C) A hyphidium. (D) Basidia. (E) Basidiospores. type PDD 112653). (B) Basidiomata (PDD 112654). (C) A hyphidium. (D) Basidia. (E) Basidiospores.
Pseudohydnum viridimontanum
Diagnosis: Pseudohydnum viridimontanum is similar to P. cupulisnymphae but can be distinguished by its smaller and mostly short-stipitate basidiomata, smaller basidiospores (5.8–6.9 × 4.4–5.0 μm), presence of cylindrical to fusiform inflated elements in the spine trama, and absence of clamp connections. In addition, it was only found on Vernonanthura discolor wood.
Etymology: viridis (Latin) = green, montanum (Latin) = hill, mount, mountain; referring to the type locality, i.e., “Monte Verde” in Portuguese, which means Green Hill.
Morphology: Basidiomata small-sized, gelatinous when fresh, pileate, laterally stipitate or pseudostipitate, solitary or in imbricate clusters, at first as a globose to bell-shaped primordia, then expanding to orbicular, flabelliform or reniform. Pileus up to 35 mm diam, surface smooth to minutely rough, white (1A1) at first, then chalk white to grayish white (1B1 to somewhat paler) or grayish yellow (1B3, 3B2); margin sharp, even to crenate, sometimes undulating. Hymenophore white (1A1) to whitish, hydnoid. Hymenophore spines sharp-tipped, up to 0.8 mm long, 2.5–4 per mm, white (1A1) to translucent white. Stipe short to rudimentary. Context concolorous with the pileus, translucent appearance when wet, thick centrally and gradually thinner toward the margin, unchanging. Odor mild. Taste mild or pleasant.
Hyphal system monomitic, generative hyphae clampless, hyphae unchanged in KOH. Pileal surface subtrichodermial to trichodermial, composed of scattered fascicles of cylindrical hyphae (2.5–5.2 µm diam) that are colorless in mass and frequently septate, thin- to slightly thick-walled; terminal elements poorly differentiated.
Contextual hyphae thin- to slightly thick-walled, hyaline, interwoven, frequently branched, commonly anastomosing, 1.5–5.0 diam. Spine tramal hyphae thin-walled toward the tips of the spines, slightly thick-walled toward the core, smooth, hyaline, branching, interwoven, 1.0–3.0 µm diam, sometimes forming intercalary and terminal inflated segments; intercalary inflated segments cylindrical to fusiform, 68–80 × 6.9–13.0 µm; terminal inflated segments long clavate, 40–85 × 9.0–14.0 µm. Hyphidia simple, thin-walled, hyaline, 1.0–2.7 µm diam at the apex, covering basidial cells.
Basidia 4-celled, longitudinally septate, multigutullate, barrel-shaped to subglobose, 9.2–12.0 × 8.1–10.6 µm; sterigmata up to 22 × 1.4–2.3 µm, mostly tubiform, usually slightly flaring at apex. Probasidia subglobose to short clavate, 8.8–9.0 × 6.5–7.5 µm, mostly multigutullate.
Basidiospores [90/3/2] (5.0–)5.6–6.9(–7.3) × (3.9–)4.3–5.0(–5.5) μm [Lm = 6,2–6.5 μm; Wm = 4.6–4.7 μm; Q = (1.16–)1.23–1.53(–1.66); Qm = 1.32–1.37], broadly ellipsoid to ellipsoid, rarely elongate, nonamyloid, nondextrinoid, acyanophilous, hyaline, thin-walled, mostly germinating by repetition, sometimes by a germ tube conspicuously long, up to 28 μm long.
Habitat and distribution: Growing on decayed wood of Vernonanthura discolor in upper montane mixed ombrophilous forest of Southeastern Brazil, at 1600 m a.s.l. Only known for the Brazilian state of Minas Gerais.
Notes: In the field, P. viridimontanum immediately evokes P. cupulisnymphae because of the white to grayish yellow pileus and occasional basidiomata with a rudimentary stipe. Both species also display similar hymenial to subhymenial anatomy. However, P. cupulisnymphae differs by its stouter and mostly sessile basidiomata, larger basidiospores (5.8–8 × 5.1–7 μm) with a lower Qm value (Qm = 1.10–1.18), clamped generative hyphae, and the absence of cylindrical to fusiform inflated segments in spine trama. Furthermore, P. viridimontanum is also different by the ontogenetic configuration in young basidiomata because at first it forms a globose to bell-shaped basidiome that rapidly expands and assumes a mature flabelliform shape. In contrast, all young stages observed throughout P. cupulisnymphae collections involve a distinctly funnel-shaped or cupulate configuration.
Figure 12. Pseudohydnum viridimontanum (holotype; NCC266, FIFUNGI292). A. Primordia and young basidiomata. B. Mature basidiomata, top view. C. Mature basidiomata, underside view. D. Hymenophoral spines detail. E. Basidia. F. Basidiospores. G. Terminal inflated elements from spine trama. H. Hyphidia. Bars: A–C = 10 mm; D = 5 μm; E–G = 10 μm.
Pseudohydnum brunneovelutinum (holotype; AGS118/2022, FIFUNGI283). A–B. Basidiomata. C–D. Detail of the hymenophoral spines. Bars: 10 mm. Photographs: Alexandre G. dos Santos e Silva-Filho.
...Remarkably, accurate analyses of all P. viridimontanum basidiomata failed to spot any clamp connections,
DICHOTOMOUS KEY FOR THE SEVEN CURRENTLY KNOWN TAXA OF PSEUDOHYDNUM FROM THE SOUTHERN HEMISPHERE
Confirmed NZ species highlighted in bold. It is likely we have other species in NZ.
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1. Basidiomata stipitate 2
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1′. Basidiomata sessile or rudimentarily stipitate 3
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2. Basidiomata confluent; basidiospores 5.5–6.5 × 4.8–5.7 μm P. totarae
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2′. Basidiomata nonconfluent; basidiospores 6.4–9.7 × 5.4–8.8 μm P. brasiliense
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3. Pileus surface brown to grayish brown, dark brown, or reddish brown; spines sparse (0.5–1.5 per mm) 4
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3′. Pileus surface whitish to grayish, grayish yellow, or pale pinkish orange; spines not sparse (≥2 per mm) 5
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4. Basidiomata sessile; simple hyphidia present P. orbiculare
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4′. Basidiomata short to rudimentary stipitate; dendrohyphidia present P. brunneovelutinum
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5. Basidiospores ≥7.2 × 6.0 μm; on Eucalyptus and Nothofagus wood; restricted to Tasmania, Australia P. tasmanicum
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5′. Basidiospores ≤7.0 × 6.0 μm; on angiosperm wood; Neotropical 6
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6. Basidiospores subglobose to broadly ellipsoid (Qm = 1.18); inflated segments in spine trama absent; clamp connections present P. cupulisnymphae
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6′. Basidiospores broadly ellipsoid to ellipsoid (Qm = 1.37); inflated segments cylindrical to fusiform present in spine trama; clamp connections absent P. viridimontanum
So P. totarae has basidiomata stipiate (which means??) vs sessile or reimentarily stipate
Spines spares and 0.5 - 1.5 per mm is P. orbiculare whereas spines > 2 per mm is P. viridimontanum
Other differences:
Clamped (P. orbiculare) vs not clamped (P. viridimontanum)
6.5–7.9 × 5.6–6.8 q= 1.17 (P. orbiculare) vs 5.6–6.9 × 4.3–5.0 Q = 1.37 (P. viridimontanum)
Pseudohydnum gelatinosum - is not found in NZ even though it is on inat.
Credit: Cooper 
