Latent Characters 219 



callus. The best instance is afforded by elms 

 and by the horse-chestnut. If the whole tree is 

 hewn down the trunk tries to repair the injury 

 by producing small granulations of tissue be- 

 tween the wood and the bark, which gradually 

 coalesce while becoming larger. From this new 

 ring of living matter innumerable buds arise, 

 expanding into leafy branches and showing 

 clearly that the old trunk possesses, in a latent 

 state, all the qualities of the whole crown. In- 

 deed, such injured stumps may be used for the 

 production of copses and hedges. 



All the hitherto recorded cases of latency 

 have this in common, that they may become ac- 

 tive during the life-time of any given individual 

 once, or oftener. This may be called the ordi- 

 nary type of latency. 



Besides this there is another form of latent 

 characters, in which this awakening power is 

 extremely limited, or wholly absent. It is the 

 systematic latency, which may be said to be- 

 long to species and varieties in the same way as 

 the ordinary latency belongs to individuals. 

 As this individual latency may show itself from 

 time to time during the life of a given plant, the 

 first may only become active from time to time 

 during the whole existence of the variety or the 

 species. It has no regular period of activity, 

 nor may it be incited by artificial stimulation. 



