42 
Garden W ork 
with the divided leaves the current flows through them 
without doing any harm. 
There is a curious phenomenon connected with the fall 
of leaves which is not very well understood, viz. Why, in 
the case of deciduous trees, the leaves become detached in 
autumn, and in the spring in the case of evergreen trees 
and shrubs, while, if a branch breaks off during the grow- 
ing season, the leaves die, but do not drop off? The reason 
is this: at the point of attachment to the branch of the leaf, 
or leaf stalk, a layer of cork cells is formed during the grow- 
ing season; very slowly at first, but as the season nears its 
end the whole plant begins to mature, and this layer of 
cork cells spreads through the whole of the 
tissue of the leaf stalk. These cork cells are 
now quite dead, and as the layer advances 
through the tissue it gradually cuts off all com- 
munication between leaf and stem, until it forms 
right through, and then the leaf drops off. 
When, however, the branch is broken off, this 
layer is not formed, and a close connection is 
maintained between stem and leaf, thus pre- 
venting the leaf from falling off, even though 
it be dead. 
INFLORESCENCE 
This is simply a collection of flowers, which 
may be formed in a raceme, as in the Wall- 
flower, with the flowers surrounding the greater 
part of the apex of the stem; or it may form 
a capitulum, as in the common Daisy. Here the ray 
flowers, which are very small, have petals tinged with 
Raceme 
Inflorescence 
