SECTION II 

 The Science of Plant Growin 



i. SIMPLE AND COMPLEX CELL LIFE 



The successful cultivation of plants requires a close familiarity with 

 their likes and dislikes, a knowledge of the conditions of their existence, 

 and how to meet those conditions to the best advantage of the culti- 

 vator; for the requirements of man are not always identical with the 

 objects of the plants themselves. By dint of practice alone and close 

 application to the art for a series of years one may become sufficiently 

 expert to grow a limited number of kinds to great perfection, but the 

 field for experiment and improvement is boundless in the domain of 

 gardening. Not merely are there plants, flowers, fruits, and vegetables 

 with which one is familiar, but new ones are constantly arising, differing 

 in some respect from those that preceded them; and hundreds of others, 

 whose cultivation is an undetermined quantity, or may have been known 

 to the successful growers of bygone times and since forgotten, may be 

 placed under the charge of the gardener. The traditions of the past have 

 not merely to be maintained, but the gardeners of the present have to con- 

 tinue the forward march of improvement, by introducing better methods 

 of cultivation wherever opportunity occurs, by improving the fruits, 

 flowers, and vegetables already under cultivation, and originating new 

 ones by the various means and methods at command. The field of 

 enquiry is wide enough for every class of worker, and the practical culti- 

 vator may avail himself of the assistance at his disposal from various 

 sources by acquiring a knowledge of the structure and nature of plants, 

 just sufficient to enable him to comprehend the meaning of the information 

 imparted by the more scientific worker. 



Simple Cell Life. A good conception of plant life in its simplest 

 form may be obtained by an examination and study of some of the 

 lower organisms, such as the green scum to be seen on damp walls or 

 the trunks of trees, where the water runs down during rain. If a minute 

 particle of this green matter (Protococcus viridis) is put in a drop of 

 water and placed under a high power of the microscope, it will be seen 

 to consist of numerous tiny green bodies of various sizes, invested by 



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