Brown cubical sap rot

Latin name: Gloeophyllum sepiarium (Wulfen: Fr.) P. Karst.
French name: Carie brune cubique
Division: Basidiomycota
Class: Aphyllophorales

Description

Micro-habitat(s)

Whole tree

Distribution

Canada

This fungus is widely distributed on dead trees and slash throughout the range of its hosts in British Columbia.

Damage, symptoms and biology

Extensive decay is indicated by the presence of fruiting bodies. Where conks are numerous, the entire sapwood and some heartwood should be considered unusable for lumber or pulp. Decay may also occur on wood in service, for example fence posts or other wooden structures.

The fruiting bodies are small, annual, leathery, shelf-like structures that generally form in cracks and checks on fallen logs. Occasionally, fruiting bodies are stalked. The upper surface is light-to-dark cinnamon brown, zoned, at first velvety but becoming roughened with maturity. The lower surface is light brown and consists of tough, radiating lamellae or gill-like structures (15-20cm, counted at margin). The context is brown.

The decay appears first as yellow to yellow-brown pockets of discolouration in the sapwood or outer heartwood. The advanced decay is a typical brown cubical rot, with yellow to yellow-brown mycelial felts in the shrinkage cracks.

Other information

This fungus is occasionally found on living trees, and on dead sapwood under scars, but most commonly on fire-killed trees and slash. The fruiting bodies of G. sepiarium could be confused with T. abietinum, but the latter has fewer (8-13/cm) and coarser gills. Other related species of Gloeophyllum have a more pore-like hymenial surface rather than gills.

Microscopic Characteristics: Hyphae in the context of the fruiting body are of three types: generative hyphae, thin to thick-walled with clamps, skeletal hyphae, (most common) thick-walled, up to 6.0 µm in diameter; binding hyphae, golden-coloured, tortuous, rare. Basidiospores cylindrical, hyaline, smooth, IKI-, 9-13 x 3-5 µm. Growth in culture slow, mat at first white then yellow-brown, laccase negative, clamps, frequent arthroconidia. Stalpers: (2) (4) (7) (8) (9) (11) 13 (14) (15) (17) 18 (21) 22 24 (25) (26) 30 31 34 35 (37) (38) (39) 40 42 (44) (45) (46) 48 50 (51) 52 53 (54) (61) 67 (75) 83 84 85 (89) (90) (93) (95) (96) 98 100.

Canadian Forest Service Publications

Brown cubical sap rot

Information on host(s)

Gloeophyllum sepiarium is found primarily on dead conifer wood, less commonly on hardwoods. In British Columbia., it has been reported on amabilis, grand, and subalpine fir, white, black, Engelmann, and Sitka spruce, lodgepole, ponderosa, and western white pine, Douglas-fir, western redcedar, western hemlock, red alder, paper birch, trembling aspen, and cherry. Elsewhere in North America it is also found on western larch, mountain hemlock, cypress, incense and yellow cedar, juniper, giant sequoia, apple, arbutus, elm, oak, sweet-gum, tulip-tree, and willow.