443 
Williamson.—The Origin of ‘ Golden ’ Oak. 
tannic acid. A consideration of these facts makes its growth on oak more 
accountable, since the tannic acid present in the wood is no deterrent to its 
activity—though it may be the factor that inhibits the growth of E. viri- 
descens on oak, since with that fungus appreciable growth was not obtained 
in tannic acid at higher percentages than o-i. 
The ‘ tannin * bodies probably contain glucosides and other impurities 
which act as food for the fungus. These bodies themselves do not appear 
to decrease, and in fact, from micro-chemical tests, would appear to be more 
prevalent in the infected wood. It may be that the clearing away of the 
impurities in the ‘ tannin ’ bodies by the fungus leaves the tannin itself more 
free to take up the ferric chloride, so producing the apparent increase in 
tannin. Without chemical analyses of the normal and infected oak it is 
not possible to be definite on this point. 
The physiological evidence points to the source of food in the wood 
being any soluble pectic bodies, glucosides, starch, proteid, and any organic 
salts that may be present. 
Summary. 
Eidamia catemdata has been isolated from the specimen of ‘ golden 5 
oak, both externally and internally. Since this fungus is the only one 
growing from inside the oak when external sterilization has been applied, 
and it also produces the golden colour when grown on normal oak, the con¬ 
clusion has been reached that the golden colour in the specimen of oak 
investigated is due to the activity of E. catemdata. 
This fungus in the infected tissue gives rise to a yellow substance as 
globules exuded along the hyphae. This accumulates in the cells and may 
finally fill them completely, with accompanying disorganization of the 
hyphae. This yellow substance somewhat resembles in its reactions the 
material termed ; wood-gum ’. 
The hyphae advance in the heartwood along the medullary rays in 
a transversely radial direction and in the wood parenchyma, fibres, and 
vessels longitudinally in the main. Passage from cell to cell takes place 
only through pits in the walls, and there appears to be no delignification 
or attack on the walls themselves. 
The source of food for the fungus in the heartwood of oak is probably 
soluble pectic bodies, glucosides, any gallic acid, starch, proteids, or organic 
salts that may occur. 
E. catemdata produces conidiophores with oval yellow conidia in long 
chains and also hyaline spores borne singly or in pairs, generally terminally, 
on lateral branches of the mycelium. 
In conclusion I desire to thank Professor Groom for passing on to me the 
original specimen of ‘ golden ’ oak on which this investigation has been based. 
