Oligocene fossil oak woods, Quercoxylon lecointrei GAZEAU & KOENIGUER, decayed by a pocket-rot fungus

Silicified fossil woods were collected from an alluvial deposit in theAllier valley, Massif Central, France. These woods, dated as Oligocene,
are identified as Quercoxylon lecointrei GAZEAU & KOENIGUER, a fossil
species close to the extant Mediterranean holm oak (Quercus ilex L.).
The specimens studied show numerous individual cavities, each 0.5-1.3 x
0.2-0.5 cm in size, but these generally do not affect multiseriate rays.
Despite the lack of fungal remains, the decay pattern is comparable in
appearance with that of present-day pocket-rot caused by Basidiomycetes,
and particularly by Xylobolus frustulatus (PERS.: FR.) BOIDIN.
Indications of possible host response to fungal attack include abundant
tyloses in vessels and dark substances filling the cells.