Conifers 
squirrel, then the next side shoot grows upwards and 
becomes a leader. Yet in a general way there are 
distinct differences both in growth and in behaviour to 
light of the main horizontal branches, and of those of 
the third and fourth order which spring from them. 
In some conifers (Cupressinez), if one makes a 
cutting from one of these side-shoots, it may grow into 
a tree, but always preserves its side-shoot character, 
never growing properly like cuttings from a leading 
shoot.” The amount of light required by the different 
trees, shrubs, and herbs differs enormously. 
Box can grow even in shade so deep that only 
one-hundredth part of the daylight reaches it. Young 
beech trees will form abundant leaves even in only one- 
fourth of the natural daylight.® 
Similar differences are found in the behaviour of the 
herbs and other ground vegetation. When, ¢.g., a great 
tree falls and light reaches the wood-floor, numbers of 
seeds, which had lain for years in the leaf mould, 
suddenly germinate. Other roots and rhizomes which 
had gone on stolidly living and forming perhaps a very 
few leaves every year, or tying up the ground by long 
branching runners without ever flowering at all, these, 
as soon as the genial sunshine touches them, awake to 
full activity and grow and flower luxuriantly. 
A very few, such as Dentaria bulbifera, prefer the dark 
shade and moist humus of the closer parts of the forest. 
Supposing, however, that such a clearing is planted 
with young conifers, they have at first a struggle against 
the nettles 5 or 6 feet high, perhaps 6 feet of bracken or 
quick springing brooms, birches, and whins ; but so soon 
as their branches begin to touch one another, the under- 
growth begins to vanish away. No seeds germinate, and 
the perennials return to subterranean runners and roots. 
The branches of the treesthen begin to compete among 
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