WINTERING AND PROPAGATING 59 



to obtain seed of some plants. Many of the 

 hardy nymphaeas produce it but rarely. 



MAKING TUBERS TO PROPAGATE 



Many hybrids are practically sterile, and 

 must be propagated from the "roots." The 

 same method may also be used for the true 

 species. Indeed, one can never depend on 

 the purity of seed where several kinds have 

 been grown in the same tank. Natural 

 hybrids are common. For pure stock of 

 tender water-lilies we must commonly have 

 recourse to the following method, beginning 

 a year in advance: 



A young plant of the desired kind is kept 

 all summer in a 6-inch pot, in very shallow 

 water. It will make good growth for some 

 time, and then all the leaves will die off. If 

 this does not occur naturally, it must be 

 induced in August or early September, by 

 raising the plant to the surface of the water, or 

 partly out. When the leaves are gone, a 

 tuber the size of a robin's egg should be 



