58 PLANT LIFE. 



the Special peculiarity of the skin or epidermis of all 

 land plants. 



The Canadian weed {Elodea Canadensis)^ which has 

 managed to establish itself in ditches and canals 

 throughout a large part of Europe, is said to have 

 escaped out of a botanical garden about 1 8 30- 1840. 

 The first record for Britain seems to have been " in the 

 canal at Foxton Lock, Market Harborough," by Miss 

 Mary Kirby in 1 847, but in the comparatively short 

 interval of seventy years it has become so common 

 that no one would suppose it to be an introduction. 

 Yet it never produces seed in this country, and spreads 

 entirely by non-sexual means. A broken branch puts 

 out new roots and develops, without difficulty, into 

 a new plant, as healthy as its parent. 



It follows that the branch which is separated must 

 contain within itself a certain amount of food material, 

 on the strength of which it is able both to produce 

 these new roots, and also to wait until they are ready to 

 perform their work. 



As a matter of fact, leaf, stem and root generally 

 contain a certain reserve of food as well as of water. 

 Thus, the leaf of a Begonia, if separated from the 

 plant and properly treated, will produce buds which 

 may develop into a new plant with flowers and seeds. 

 Willow and Geranium cuttings are simply cut off 

 branches. The stump of an ordinary tree, such as the 

 oak, will throw out branches, which may become trees, 

 quite as large as any that are formed by seed. 



This property is of great importance to mankind, 

 because many varieties of cultivated plants do not seed 

 freely, and may, perhaps, take a very long time to 

 mature ; whilst by these methods of propagation a 

 new plant, which retains all the valuable properties 



