395 
Sugar-Cane in the West Indies. 
Longitudinal sections of the dwarfed roots showed that 
the root-cap and cortex were invaded in all directions by 
a mycelium characterized by clamp-connexions and brown, 
thick-walled, chlamydospore-like bodies (Fig. io). These 
tissues and the whole of the periblem were dead, much disin- 
tegrated and dark brown in colour in many places. The 
pleurome was often invaded by similar mycelium, and the 
growing-point destroyed. Attempts were frequently made 
by such roots to branch, but the secondary roots were usually 
destroyed before the cortex of the parent root was penetrated. 
The beginning of such attempts is shown in Fig. n. 
The undeveloped roots, which were characterized by brown 
marks in the rind of the cane immediately over them, were 
found to be destroyed in a very similar manner to those in 
which growth had been arrested shortly after penetration 
of the rind. Longitudinal sections showed that the periblem, 
and often the pleurome too, were invaded by the above- 
described mycelium. The root-cap, digestive sac, and growing- 
points were in all cases destroyed (Fig. n). The mode of 
entry of the fungus into the developing root varies. In some 
cases it passes from the exterior through the digestive sac 
and root-cap and invades the growing-point tissues direct. 
In others, it passes between the young root and the surround- 
ing tissue of the stem and invades the periblem from below, 
passes upwards, and finally overcomes the growing-point. 
No matter whether the roots are destroyed just after 
penetration of the parent stem or before this is accomplished, 
the result is the same, namely, the loss of a possible means 
of supplying the cane with water and minerals from the soil. 
When, as in most cases of this disease, by far the greater 
number of the roots in the below-ground portion of the stem 
are destroyed in this way, as well as those for some distance 
above the ground, it is clear that recovery is out of the 
question. 
If the development of the shoots which arise from the buds 
at the base of the parent stem is followed, it is found that 
here too the leaf-sheaths become cemented to the stem by 
D d 2 
