CLIMBING AND WATER PLANTS 113 
these anomalies are of obvious advantage 
to a climber, and are calculated to minimise 
risk of damage to the conducting channels 
of the stem under the special circumstances 
of their habit of life. The main stem is 
sometimes lobed, and it may ultimately even 
split into a rope-like mass of cordage. Or 
it may be flattened and wavy in contour, 
a character obviously associated with con- 
siderable resilience. Again, the soft phloém 
is frequently embedded amongst the woody 
tissues, and is thus shielded from injury 
such as might arise through torsion of the 
stem, and in other ways. 
But it is not true that every specialised 
climber is provided with a special or anomalous 
stem structure, nor are these abnormalities 
confined to climbing plants. The facts seem 
to indicate that the anomalies in question 
are to be regarded as instances of a break 
away from traditional structure, that they 
owe their origin primarily at least to the 
inner constitution of the living substance of 
the ‘plants in which they arise. They may 
be regarded as one of the expressions of 
inherent tendency to vary which in dominant 
groups of plants is seen in a multiplication 
of related species. Any such break away 
from the type form of structure may prove 
useful in enabling a plant to develop new 
functions, or more perfectly to discharge 
nascent ones. And there are a very large 
number of instances, of the most varied 
H 
