[Vor. 1 
244 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
tached from each other, so that it is diffieult to get flawless 
boards." 
In 1912 the writer found the older mesquite trees in the 
vicinity of San Antonio, Texas, seriously affected by a trunk 
disease, caused by one of the polyporous fungi. In one small 
field some twenty or more trees were found bearing the fruiting 
bodies of this fungus. Its distribution in the vicinity of San 
Antonio was general, and it is probable that it extends over а 
wider range, as evidenced by the finding of a sporophore by 
Underwood in the vicinity of Austin, in 1891. 
Where the mesquite develops into a bush with several trunks, 
sometimes only one of the several trunks is affected, but in 
other cases several or all of them contract the disease. Тһе 
age of the affected trees was difficult to estimate. "The mesquite 
grows rather rapidly at first, but very slowly after eight or ten 
years. According to Sargent, trunks thirty years old may be 
seven to eight inches in diameter, while trees one foot in diam- 
eter are probably over one hundred years old. Тһе trees 
found affected were from two to ten inches in diameter and 
all over twenty years of age, some of them probably very much 
older. 
The decay is confined entirely to the heart-wood of the main 
trunks, extending from the ground up into the trunk for varying 
distanees. Тһе distribution is such that it is obvious that the 
fungus gains entrance through wounds in the trunk above the 
ground, chiefly through old branch stubs and borer holes, as is 
во frequently the case with trunk diseases of this kind. One 
instance was found which made it appear obvious that the holes 
made by the borer had served to give the fungus a start. 
Sections of diseased trunks showed that the heart-wood was 
decayed to a greater or less degree (pl. 6 fig. 2). Mesquite 
wood has very sharply defined heart and sap-wood. The latter 
is light yellow or almost white and very narrow, being composed 
of but a few rings of wood, whereas the heart-wood is rich brown 
orreddish. Тһе decay of the heart-wood begins near the center, 
and gradually spreads outward towards the bark; there is very 
little, if any, change in color (except that the decayed wood is a 
lighter shade of brown), and here and there irregular, thin lines 
of undecayed wood can be seen extending through the diseased 
