THE GARDENER'S ASSISTANT 



CHAPTER I. 

 PLANT STRUCTURE. 



Conditions of Existence— Structural Elements — 

 The Cell and its Contents — Protoplasm— Modi- 

 fications of Cells— Pitting — The Thallus. 



The gardener has to deal with those living 

 beings which are known as plants. The life of 

 a plant and its fundamental construction are, 

 broadly speaking, identical with the life and 

 with the construction of an animal. It is not 

 necessary here to point out in what minor par- 

 ticulars plants differ from animals; all that is 

 necessary at this stage for the gardener to 

 realize is the fact that a plant is as much a 

 living creature as an animal. It has to exist, 

 to grow, to reproduce itself. It does all these 

 by availing itself of the circumstances in which 

 it is placed and by utilizing the materials which 

 surround it. Work of this character could not 

 be carried on without machinery, and this ma- 

 chinery is supplied by the structural elements 

 of which the plant, like the animal, is made up. 

 To enable the plant to maintain itself, to 

 grow and develop, it requires to be placed within 

 a certain range of temperature which must be 

 neither too high nor too low; it requires food, 

 or substances capable of conversion into food, 

 and these substances are derived from the water 

 in the soil or from the atmosphere. It requires, 

 in fact, to breathe, to feed, to exhale, and to be 

 protected against adverse conditions. Special 

 conditions come into play when the plant repro- 

 duces itself. Hence it is that a plant has to be 

 considered not only for itself, but also in rela- 

 tion to its surroundings and to the conditions of 

 its existence — in relation, that is, to heat, light, 

 air, water, and soil. The physiologist in the 

 laboratory can study the effects, say, of light 

 apart from those of heat, but the gardener never 

 has the chance of studying the plant in this 

 simple manner. He has to study it as it grows 

 in nature or under cultivation, subjected to the 



combined and simultaneous influence of diverse, 

 and it may even be conflicting causes. In a 

 wild state the plant has more or less power of 

 adapting itself to these varied conditions, more 

 or less means of resisting adverse influences of 

 all kinds. If its powers of adaptation and resis- 

 tance are sufficient, the plant will thrive and 

 multiply. If, on the contrary, its endowments 

 are inadequate, the plant will gradually dwindle, 

 be elbowed out of existence by its better- 

 endowed competitors, or become the prey of 

 parasitic enemies. 



Under cultivation the plant is, so far as pos- 

 sible, removed beyond the reach of its enemies, 

 and it is, or should be, placed under the most 



I favourable conditions, so that it may become a 

 "model of good cultivation". It must not, 

 however, be overlooked that the qualities that 

 gardeners prefer and seek to develop are not 

 always those which are best for the plant itself. 

 The plant's necessities and our requirements are 

 not by any means always identical, so that it 

 very often happens in cultivation that we do 

 what is best for ourselves, but not that which is 

 best for the plant, and we succeed in producing 

 a monster or a deformity, where Nature, left to 

 herself, would have produced something quite 

 different. Compare, for instance, a broccoli 

 with the wild cabbage. But, in any case, the 

 general principles of cultivation are the same, 

 even though in practice we have to modify them 

 to suit our requirements or the exigencies of 

 circumstances. 



From what has been said, it is evident that 

 we have, first, the plant and its structure to 

 consider; then the conditions under which it is 

 placed — the "environment", as it is called; and 

 lastly, the way in which the plant turns to 

 account the conditions by which it is sur- 

 rounded, and the influence of those conditions 

 separately and in combination. To carry out 

 such a programme fully the student must needs 

 be at one and the same time a botanist, a micro- 



1 scopist, a chemist, a physicist, and a physiologist. 



