Dec. 8,1993 
The Red Stain in the Wood of Boxelder 
449 
have not been examined. Eidam states that a similar “blood red” 
discoloration was noted in a piece of beech wood, and records the finding 
by Stein of a “beautiful violet stain” in the wood of lilac (Syringa 
vulgaris). A bright violet-red color has been observed by the writer 
in a piece of lilac wood in the wood collection of the Forest Products 
Laboratory. 
CAUSE OF THE DISCOLORATION 
The discoloration in the wood of boxelder is due to a soluble pigment 
secreted by the fungus which stains the wood tissues and cell contents 
and by the presence in the wood of colored hyphae. The older hyphae 
within the wood tissues contain the coloring matter, as do also the hyphae 
in most of the cultures. An experiment was conducted to determine 
whether the coloring matter was to be found in solution outside the 
hyphal threads. Two tubes of malt agar on which the organism had 
been growing for a period of eight days were emptied of their contents 
upon a paper filter. Warm distilled water was poured over the agar 
and the collected filtrate showed a distinct reddish color. The formation 
of brighter colors is apparently favored by an acid medium, probably 
by the degree of acidity, since the areas of the heartwood showing the 
bright red colors react quite strongly acid to litmus, while the yellowish 
to brownish areas accompanying these react but slightly. 
That the coloring matter diffuses out from the fungus and is not 
confined to the lumen of the hyphal cells is evidenced by the observations 
that hyphae are not always found in the red colored tissued. Apparently 
the colored liquid diffuses considerably beyond the hyphae which pro¬ 
duce it. The color fades somewhat when a red-stained boxelder board 
is exposed for a year to sunlight. 
DESCRIPTION OF STAIN 
The red stain in boxelder varies considerably both in shades of color 
and in uniformity of distribution throughout the tree. The color ranges 
on moist wood from a light coral red to hellebore red or carmine. 7 On 
dry wood the hues are less intense and range from light coral pink to 
jasper red. 
Very often the stain in the heartwood does not show a uniform coloring, 
but is broken by irregular blotches of various sizes and of a deeper hue 
(pi. 3). These blotches indicate individual infections due to sapsucker 
injury. Very frequently the heartrots caused by Collybia velutipes 
Curtis, Pleurotus ulmarius Bull., Fames applanatus Fr. or other poly¬ 
pores are found in the heartwood (pi. 3). In such cases the red stain 
is found bordering the decayed areas and frequently the decayed area 
contains the red stain which had previously surrounded it but had 
become invaded by the advancing rot organisms. No particular signs 
of antagonism to one another is exhibited in wood containing the red 
stain fungus and a heartrot organism. When the red stain is present 
in the same areas with F. applanatus the latter fungus produces narrow 
black zone lines along the outer boundaries of the decayed areas (pi. 3), 
but these lines are not consistently formed, so there is no indication 
that they are due to a reaction between the two fungi. Similar lines 
are formed by Fomes applanatus in the absence of other fungi. 
7 Rzdgway, Robert. cou>r standards and cou>r nomenclature. 43 p.» 53 col* pt Washington,. 
D. C., 19 X 3 . 
