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IX. — On Sfraic- Blight, a Disease of Wheat-Sfraw. By W. 
Carruthers, F.R.S., F.L.S., Consulting Botanist. 
The first indication of this disease is the occurrence of small 
brownish spots on the surface of the straw towards its base, 
general I V below the 
first joint from the 
root, or between that 
and the second, or 
sometimes as high 
as between the se- 
cond and the third 
joints. These spots 
become darker in 
colour and increase 
in size, becoming of 
an irregularl yround- 
ish or oblong form, 
and ultimately be- 
coming confluent. 
A careful examina- 
tion of the stem 
shows that they are 
not superficial, but 
depend on changes 
in the interior of the 
stem. On applying 
the microscope to 
prepared sections, it 
is found that the 
solid part of the 
stem, below the 
coloured spots, is 
penetrated bv the 
branching and con- 
jointed mycelium of 
a fungus, similar to c 
that which has pro- 
duced such havoc to 
the potato crop for 
so many 3'ears. The 
filaments of the 
mycelium are extremely fine, repeatedly branch, and frequently 
anastomose. Only here and there a slight indication of 
joints, or horizontal partitions, appear. This mycelium passes 
Section of a straw 
showing cott<in 
masses of mycel 
peneti ating the hoi 
low straw. 
B. Section of the straw 
masmifieil luO times. 
a, the outer surface 
of ihe straw ; b, the 
mycelium pene- 
trating the cavity 
of the stem. 
everal cells magnified 
300 times, showing 
the br.mching and 
anastomosing fila- 
ments of the my- 
celiam. 
