GENERATION OF PLANTS. 63 



LESSON IV. 



GENERATION OF PLANTS. Multiplication of Plants In/ Division 

 Formation of adventitious Roots Multiplication of Plants 

 by Grafting ; by Tubercles Phanero gamous and Cn/pfo' ga- 

 mous Plants defined Structure of Flowers Peduncles Pedi* 

 cii Floral Leaf Bract Involucre Spatke Glume 

 Torus Receptacle Inflorescence Perianth Calyx Co- 

 rolla Petals Forms oj tlue Corolla Nectary JKstivation 

 Essential Parts of Flowers Stamens Anther Pollen 

 Pistil Carpel Ovary. 



OF THE REPRODUCTION OF PLANTS. 



1. The multiplication of plants takes place in two ways ; some- 

 times by means of special organs, designed to produce the germ 

 of the new individual, and sometimes by the simple division of 

 their tissue. 



2. The multiplication of plants by division consists in tho 

 separation of a part of an individual, which part continues to 

 vegetate, and becomes so complete in itself as to constitute, in its 

 turn, a new individual plant. 



3. This phenomenon depends upon the fact that the different 

 parts of a plant, placed under favourable circumstances, have a 

 tendency to produce those organs which are wanting to constitute 

 a complete plant, and that the portion which gives rise to these 

 complementary parts becomes fit to live without the assistance of 

 the individual from which it was taken. For example, a branch 

 placed in favourable circumstances may put forth roots (which 

 are called adventitious when they arise in this way, as before 

 stated in page 18), so that, if it be separated from its stem, it 

 will still continue to be nourished, and will constitute a new indi- 

 vidual ; the same is true of roots ; they also have the faculty of 

 giving rise to sterns and to leaves ; and a root from which a stem 

 and leaves arise possesses all the organs necessary for vegetation, 

 and consequently may continue to live after it has been separated 

 from the plant of which it at first formed a part. 



4. Gardeners give the name of shoots or slips to those branches 

 from which they cause adventitious roots to spring, and which 

 they then separate from the parent plant. In general we succeed 



1. How is the multiplication of plants effected ? 



2. What is meant by the multiplication of plants by division 



3. Upon what does the multiplication of plants by division depend ? 



4. How are adventitious roots artificially produced ? 



