374 



The Living Plant 



in reality is a land of fasciation. It is perfectly impossible to 

 draw any sharp line between these different forms of clustered 

 abnormal growths, or between external and internal causes of 

 their formation. 



Somewhat similar is the origin of twisted stems or torsions. 

 These occur in small herbs, but are often seen to perfection in 

 dead standing trees, or even in the logs of fence rails ; but here the 



-»^5 ' \ 



Fig. 144. — A fasciated Pineapple, resulting from causes explained in the text. 



process is hardly abnormal, since, as seems likely, the twisting of 

 the cambium cylinder, to which it is due, is a result of normal 

 growth processes in the plant. 



A second common form of monstrosity is that known as pro- 

 liferation. Sometimes the stem of a pear, or a strawberry (fig- 

 ure 145) grows on beyond the fruit, producing there a cluster of 

 leaves. In one way these cases are easy to understand, for they 



