CUTTINGS 259 



and after the death of the bare internodes form separate 

 plants. 



Other examples of vegetative multiplication are seen in the 

 growth of bulbous and corm-bearing plants (pp. 56-60). 



3. In addition to the natural modes of reproduction just 

 mentioned, various artificial modes of vegetative propagation 

 are known. Detached pieces of the roots, stems or leaves of 

 many plants when placed under certain conditions indicated 

 below, give rise to those organs which are necessary to make 

 the part a complete plant : thus the shoots of plants when cut 

 off and placed in suitable soil soon develop a system of ad- 

 ventitious roots, and pieces of roots treated in a similar manner 

 produce buds from which leafy shoots arise. It is a remarkable 

 fact that although roots may be formed when either end of a 

 cutting is inserted in the earth, the best development of roots 

 always takes place when that end of the cutting which was nearest 

 the root of the parent plant is buried in the soil. Also when a 

 root-cutting is buried in the ground, the greatest growth of roots 

 originates from that end of the cutting which was nearest the apex 

 of the root, the other end giving rise to adventitious buds. The 

 severed shoots of certain conifers and other plants do not appear 

 to be able to form roots, nor are their roots capable of forming 

 buds : plants such as these cannot be reproduced vegetatively. 



The commonest examples of artificial vegetative reproduction 

 are seen in the propagation of plants by means of cuttings and 

 layers and in the processes of budding and grafting so extensively 

 practised by nurserymen and gardeners. 



4. Cuttings. — The term cutting is applied to any portion of a 

 root, stem or leaf cut from a plant and used for propagation. 

 A few plants, such as pelargoniums, have the power of forming 

 adventitious buds upon cut portions of their roots, .and may be 

 propagated by root-cuttings. The leaves of gloxinias, begonias' 

 and other plants, when cut through the midribs and fastened 

 down or merely laid on damp sand, and kept at a suitable 



