Basidiocarp resupinate, effused, adnate, seasonal (perennial ?), covering large area, up to 175 x 25 mm, 1-1.5 mm thick. Margin absent or present, then irregular, effused, 1-2 mm wide, whitish to creamy, sometimes with yellowish tints, cottony. Pore surface even to slightly nodulose, creamy to pale orange, pale greyish orange (5A(3-(4)), 5B(3-4)). Pores round to elongated on sloppy substrate, 5 or 6 per mm, 100—150—(175) µm diam. (x= 126 p-m). Dissepiments entire, thick, smooth. Tubes in one or two (7) indistinctly stratified layers, 0.5 mm long, elongated, up to 2 mm long on sloping surface, concolorous with the pore surface. Subiculum whitish cream to pale greyish orange, tough, with a cottony texture, almost absent to 0.5 mm thick.

Hyphal system di-trimitic in both subiculum and trama of the tube. Generative hyphae hyaline thin-walled, clamped, 2-3 µm wide. Vegetative hyphae hyaline, nondextrinoid (yellowish in Melzer's reagent), cyanophilous. Context with laxly branched vegetative hyphae, difficult to separate, thick-walled, with an open lumen, with an ill defined branching pattern, with long, straight to sinuous, or geniculated branches, 2.0-2.5-(3) µm diam. in the basal part, with branches 2.0-2.5 µm diam. down to 1.3-1.5 µm wide at the apex. Trama of the tubes mainly composed of variably branched vegetative hyphae, with an arboriform branching pattern, from much branched, binding-like to sparingly branched, almost skeletal-like. Basal stalk (20)-25-67-(90) µm long (x - 49 µm), with a basal clamp, progressively widening from 1.5-2.5 µm (x = 2.0 µm) wide at the basal septum to 2.5-3.0 µm (x = 2.7 µm) at the branched apex, straight to geniculate, occasionally with bulbous, intercalate or terminal swellings, 6-10 µm wide, occasionally with lateral aborted processes, and with 1-3-(4) subapical or apical branches. Branches usually straight, sparingly branched (0-1-2 dichotomy), 1.5-2.0-(2.5) µm wide (x = 1.7 µm), measured up to 140 µm long, apices rounded, thin-walled. Branches tend to be longer, straighter, almost skeletal like near the centre of the trama or the subiculum, and shorter, more branched, quasi binding-like, near the hymenium or the dissepiments, where they often abort.

Basidia 22-24 x 8-9.5 µm, mostly collapsed, few mature, clavate to pedunculate, clamped at the basal septum and with four sterigmata. Basidioles 14-25 x 7.0-9.5 µm (x = 19.2 x 8.4 µm), clavate to pedunculate, clamped at the basal septum. Basidiospores (6.0)-6.2-7.3-(7.5) x (4.5)-5.2-6.0-(6.2) µm, R= 1.1-1.4 (x =6.8 x 5.6 |µm, xR= 1.2), broadly ellipsoid to subglobose to ovoid, apex rounded to distinctly truncate, thick-walled, with 0 or 1 guttules, hyaline, cyanophilous, strongly dextrinoid. Cystidia and chlamydospores none.

Type of Rot: white rot.
Cultural Features: unknown.
Sexuality: unknown.

Perenniporia cunninghamii is probably related to Perenniporia medullapanis. It differs from the latter by possessing larger basidiospores on average. However, the range reported for the latter species is variable. Ryvarden and Johansen (1980) reported 4.5-7.0 x 4.5-6.0 µm, Ryvarden and Gilbertson (1994) 5.0-6.0 x 3.5-4.5 µm, Gilbertson and Ryvarden (1987) 5.0-6.5 x 3.0-4.0 µm, and Cunningham (1965) 5.0-7.5 x 4.0-5.5 µm as basidiospore dimensions for P. medullapanis. As used by most authors, P. medullapanis probably represents a species complex. There is no other Australasian taxon to which P. cunninghamii can be compared. Perenniporia subaurantiaca has ellipsoid oblong, non-truncate basidiospores. Perenniporia podocarpi differs in basidiocarp morphology, basidia (see below) and larger basidiospores. It is a matter of opinion whether the hyphal system in the trama of the tubes is called di- or trimitic, although for pragmatic reasons, we call it di-trimitic. The trama of the tubes in P. cunninghamii is composed of variably branched vegetative hyphae, mainly with an arboriform branching pattern, although the latter pattern can be strongly reduced. The length of the branches and the degree of branching is variable, ranging from vegetative hyphae with one or two long straight, almost skeletal-like branches to vegetative hyphae with more numerous, shorter binding-like branches (Fig. lb). However, intermediates exist, forming in fine a continuum from one extreme to the other. Reduction of the branching and elongation of one (or two) ramifications can lead to skeletal-like hyphae. Branching and branch length might also vary with localisation within the trama, with an increase of branching and shortening of branches from the subiculum or the core of the trama toward the hymenium or in the dissepiments area.