66 {EPORT OF THE BOTANIST OF THB 
THE STEM ROT. 
In December, 1898, we observed a stem rot or perhaps it might 
more appropriately be called a branch blight working among some 
Antirrhinums in one of the Station greenhouses. During the 
remainder of the winter and the following spring this disease 
became common and caused considerable damage. The same dis- 
ease appeared again last winter, but not so destructively. 
It attacks chiefly the succulent shoots, causing several inches 
of the termina] portion to wilt and die. In some cases, particularly 
on shoots which have become somewhat woody, a section of the 
stem an inch or more in length turns brown, while the portion 
beyond remains green. In a short time, however, the whole 
branch dies. More frequently all of the affected portion wilts 
and becomes discolored without the appearance of a spot at any 
particular place on it. The point of attack may be close to the 
soil, but is usually at considerable distance above it, and never 
below it so far as observed. 
In all cases numerous pycnidia of a species of Phoma soon 
make their appearance on the lower part of the affected portion. 
In the course of the investigation other fungi were sometimes 
found on the diseased stems, but the Phoma was so abundant and 
so constantly present that it was suspected to be the cause of 
the trouble. Pure cultures of the Phoma were obtained and 11 
succulent shoots inoculated with it, as follows: About three 
inches below the tip of each shoot a puncture was made, a small 
quantity of fungus inserted, and then the puncture covered by 
wrapping the stem with grafting wax. Ten check shoots were 
treated in identically the same manner, except that no fungus was 
inserted in the puncture, 
The inoculations were made April 30th. At the end of five 
days four inoculated shoots were wilted; two more wilted on the 
eighth day, two others on the ninth day, and on the eleventh day 
all eleven inoculated shoots were fully wilted. Seven of them had 
rotted so badly at the point of inoculation that they had broken 
over and the tops hung down. As late as June 19th, seven weeks” 
