il! Fururn Borantist. 
tation. In England, for instance, we have many annuals, and in 
Tripoli and Egypt there are numerous tiny forms whose life is 
confined to the few days during which the soil is kept moist by a 
shower of rain. They spring, blossom, and die in perhaps three 
days. ‘The fact that many of our annuals are perennial at the 
Cape proves that there is no real distinction between the two 
forms. 
Every tree and shrub, again, has a method of branching 
peculiar to itself, but varying much according to the particular 
situation. This depends on which of the possible buds are allowed 
to develop, and how long each is able to grow before it is checked. 
Thus, in a very sunny or windy place a twig grows only a 
very short distance. Its tissue soon becomes so thick that it can- 
not elongate, though it may become wider ; it therefore stops, and 
another bud sends out a little twig which stops, and yet another, 
and so or. The result of this is a dense twiggy branching which 
one finds typically in plants growing by the sea or in exposed 
places. 
Another important effect of the development of the stem is 
the rosette type of plant, such as, eg., the daisy. Here the inter- 
nodes are suppressed as a result apparently of exposure, for many 
of these rosette forms will develop internodes if grown in moist, 
half-shaded places. Ilowever produced, the rosette shape is 
characteristic of plants that grow on bare earth, and whose leaves 
can lie flat down upon the soil. The plant gains by this structure, 
for its cushion or rosette of leaves retains dew, and keeps the earth 
below moist, while not having an expansive stem to make, the 
plant can send a long root mto the rock crannies, or use up its sur- 
plus material in flowering branches or in vivid colour. In this 
case you see the climate or exposure, by suppressing the internodes, 
forms a rosette of leaves flat on the ground, which isa form exactly 
suited to the circumstances. 
This is a good example of how plants have a certain structure, 
and also of how these have been produced. ‘To give a good 
idea of the present theory of the origin of variations, as I hold 
it myself, it is necessary to go a step or two further. We 
will suppose that a species of an ordinary kind of Mieracium, 
common in glens and corries, has had a seed blown by wind 
to an exposed rock ledge at some distance off. The exposed 
situation will have the effect of suppressing the internodes so that 
