Geographic and host distribution. Amylofungus corrosus is known only from New Zealand. According to Cunningham (1963), specimens of this species have been collected from several families of deciduous trees.

Basidiomata resupinate, effuse, ceraceous, 40-120 µm thick. Hymenial surface yellow, smooth. Monomitic. Subiculum thin, with compact texture, hyphae colorless, 1.5-3 µm, thin-walled. Subhymenium ± thickening. Gloeocystidia irregularly cylindrical or clavate, sometimes long-acuminate toward apices, 20-60 x 6-12 µm, thin-walled, amyloid, SA+. Basidia utriform, 33-43 x 5-7 µm, four-sterigmate, amyloid. Basidiospores globose to subglobose, smooth, thin-walled, 5.5-6.5(-7) x 4.5-5.5 µm, amyloid.

This description is based on the holotype (see also Cunningham, 1963; Stalpers, 1985).
This species was tentatively placed in Gloeocystidiellum by Stalpers (1985), but Gloeocystidiellum s. s. has clavate basidia and ornamented basidiospores. The basidioma of the type specimen (PDD 11350) has been largely destroyed; it was probably eaten by invertebrates attracted by the fragrant gloeocystidia. This attraction was also mentioned by Cunningham (1963, p. 58).

Specimen examined. NEW ZEALAND. AUCKLAND: Mt. Hauhangatahi, 900 m, on Neopanax colensoi, Feb. 1952, G.H. Cunningham (PDD 11350, HOLOTYPE).

Basidiomata resupinate, effuse. Hymenial surface smooth. Hyphal system monomitic. Hyphae simple-septate, amyloid. Gloeocystidia numerous, clavate or cylindrical, SA+, amyloid. Basidia utriform, four-strigmate, amyloid. Basidiospores globose or subglobose, smooth, thin-walled, amyloid.

Basidiocarpum resupinatum, effusum; superficies hymenialis plana. Systema hypharum monomiticum. Hyphae efibulatae, amyloideae. Gloeocystidia numerosa, cylindrica vel clavata, SA+, amyloidea. Basidia utriformia, 4 sterigmatibus, amyloidea. Basidiosporae globosae vel subglobosae, laeves, tenuitunicatae, amyloideae.

Etymology. From amylo + fungus, referring to the amyloid reaction of the whole fruiting body.
Amylofungus is characterized by the presence of amyloid hyphae, gloeocystidia, basidia and basidiospores. This is the only genus of basidiomycetes that combines these characters. Moreover, the utriform basidia and smooth basidiospores are also characteristic for this new genus. The simple-septate hyphae, as well as subglobose-globose and smooth basidiospores, indicate a close affinity between Amylofungus and Gloiothele.

Typus. Corticium corrosum G.H. Cunn.

Specimen examined. NEW ZEALAND. AUCKLAND: Huia, 30 m, Kawhia Harbour, coast, on stump of Leptospermum scoparium J.R. & G. Forst., 18 Jan. 1953, J.D.Atkinson (PDD 11845, HOLOTYPE).

Basidiomata resupinate, effuse, subceraceous or ceraceous. Hymenial surface pale pink, smooth, cracked. Dimitic. Generative hyphae simple-septate. Subiculum thin, with compact texture; hyphae colorless, usually glued together, 2-3 µm diam, thin- or slightly thick-walled. Subhymenium distinctly thickening, with compact texture. Skeletal hyphae occasionally branched, colorless, 3-4 µm diam, thick-walled, nonamyloid, nondextrinoid. Lamprocystidia numerous, overlapping in context, colorless, subulate, 30-50 x 7-12 µm (with encrustation), with 0.5-1.5 µm thick walls, dextrinoid and cyanophilous. Gloeocystidia rare, cylindrical, flexuous, colorless, 25-45 x 3.5-6.5 µm, thin-walled. Basidia utriform, 35-40 x 6.5-8.5 µm, slightly thick-walled, four-sterigmate. Basidiospores broadly ellipsoid, adaxially slightly concave, verrucose (smooth in KOH), slightly thick-walled, 8.5-10.5 x 5.7-7 µm (in KOH), amyloid.

Geographic and host distribution. Dextrinocystidium sacratum is known from Australia and New Zealand. Collections of this species have been made from several families including deciduous and coniferous trees (Cunningham, 1963).

This description is based on the holotype; see also Cunningham (1963) and Stalpers and Buchanan (1991).
This species has been transferred by Taylor (1981) to Phanerochaete Karst., by Burdsall (1985) to Amylostereum Boid., and was placed by Stalpers and Buchanan (1991) in Gloeocystidiellum. However, no species of Phanerochaete has amyloid basidiospores. Amylostereum is a clamped genus, which is also characterized by apically encrusted brownish cystidia and smooth basidiospores. Dextrinocystidium is distinguished from Gloeocystidiellum s. s. in having utriform basidia and dextrinoid and cyanophilous lamprocystidia. Skeletals in D. sacratum have not been reported before, but they are not difficult to find in sections of basidiomata. Skeletal hyphae are nondextrinoid and acyanophilous and occasionally branched; therefore, they are not the basal part of lamprocystidia. Gloeocystidia are rarely present in the holotype (PDD 11845) of this species, and were described as weakly sulphoaldehyde-positive by Stalpers and Buchanan (1991). This positive reaction could not be confirmed by me, based on the studies of the holotype. However, this reaction can be accurately tested based on fresh specimen. Stalpers and Buchanan (1991) have mentioned that cultures of D. sacratum display occasional septa with one to three clamps. Taylor (1969) proved that root canker of apple trees in New Zealand is caused by this species.

Basidiomata resupinate, effuse. Hymenial surface smooth. Dimitic. Generative hyphae simple-septate. Skeletal hyphae occasionally branched, nonamyloid, nondextrinoid. Lamprocystidia present, dextrinoid. Gloeocystidia present. Basidia utriform, four-sterigmate. Basidiospores broadly ellipsoid, verrucose, amyloid.

Basidiocarpum resupinatum, effusum; superficies hymenialis plana. Systema hypharum dimiticum. Hyphae generatoriae efibulatae. Hyphae skeletales aliquando ramosae. Lamprocystidia praesens, dextrinoidea. Gloeocystidia praesens. Basidia utriformia, 4 sterigmatibus. Basidiosporae late ellipsoideae, verrucosae, amyloideae.

Etymology. From dextrino + cystidium, referring to the dextrinoid reaction of the lamprocystidium.
Dextrinocystidium is characterized by the presence of dextrinoid lamprocystidia, clampless generative hyphae, branched skeletals, utriform basidia and verrucose basidiospores. Scytinostromella also has branched skeletals and basidia of a similar shape, but lacks the dextrinoid and cyanophilous lamprocystidia. Moreover, Scytinostromella is a clamped genus, with loose texture in the subiculum, and has much smaller basidia and basidiospores.

Typus. Peniophora sacrata G.H. Cunn.