Sy 
THE ‘‘BLUE”’ FUNGUS. 25 
the hyphe and fruiting bodies of the fungus. The green matter, 
xylindeine, is confined to the fungus threads and in no way stains the 
wood fibers. Vuillemin states expressly (p. 144) that ‘‘there is no 
green decay or green staining of the wood. The wood appears green 
when the colored thallus of Helotium xruginosum or of analogous 
fungi is found in its elements.” With the highest powers of the 
microscope he was unable to find any coloration of the walls of the 
wood. The green color is therefore due to the presence en masse of 
ereen-colored threads. 
Similar instances of color due to the presence of colored mycelium 
are found on pine and spruce wood, where brown and black lines are 
formed by masses of dark hyphe bunched at particular points in the 
wood cells. The familiar zigzag and fantastic lines often found in 
wood of the tulip tree and in birch and maple are due to similar fungus 
threads. In none of these cases are the wood fibers themselves colored. 
So far as known to the writer, no attempt has ever been made to 
explain the nature of the blue color of coniferous woods. The color 
is a difficult one to define. A number of the writer’s artist friends 
who were called into consultation pronounced it a blue gray, approach- 
ing Payne’s gray. Freshly cut wood looks decidedly blue, but as the 
wood dries the color fades somewhat and dry wood is mouse gray. 
The color is by no means regular; here and there some of the yellow 
of the healthy wood shines through. The drawing shown on PI. I is 
perhaps a little too blue. Pl. V is closer to the real color. Certain 
portions of the blued wood look greenish when viewed obliquely. 
There are two possible explanations as to the cause of the so-called 
blue color: (1) The wood may appear colored because of the pres- 
ence of the colored fungus threads in the wood. The mass effect of 
such colored threads might make the wood appear colored. (2) The 
wood might be colored by a pigment or stain formed either by the 
fungus or as a result of the fungus growth in the wood, and this 
pigment might stain the walls of the wood fibers. 
The first explanation holds good for the ‘‘green” wood. Here a 
pigment is formed in the hyphe and fruiting bodies of the fungus, and 
it is because of the presence of the green-colored bodies in the fungus 
threads, according to Vuillemin, that the entire wood looks green. 
Careful examinations made of the ‘*‘ blue” wood by persons trained to 
observe colors, called into consultation by the writer, have led to somie- 
what conflicting results, and it is therefore thought inadvisable in the 
present stage of the investigation to enter on a lengthy discussion of 
the color subject. A number of facts may be stated, however. Exam- 
inations of the wood fibers of sound and ‘‘ blue” wood showed that it 
was possible in most instances to distinguish between the sound and 
the ‘‘blue” wood. The walls of the sound wood look somewhat 
darker (with a suggestion of purple) than the blued fiber. This method 
