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.