the trunk lengthens. We find that even the trunks of 

 old dicotyledonous trees, below the part where the boughs 



Lodotcea lecktUarum. 



set on, are nearly cylindrical, or frustra of very elongated 

 cones, when compared with the portions above them. 

 Mirbel has figured the trunk of a monocotyledonous 

 tree which has become completely invested by a climber 

 whose branches have grafted together into a reticu- 

 lated cylindrical mass. This specimen has been consi- 

 dered to illustrate the fact, that the stem could not have 

 increased at all in thickness after it had become so 

 closely embraced. But something of the same sort may 

 occasionally be observed even in dicotyledonous trunks, 

 where they have become completely invested by ivy, 

 whose branches intertwine and graft together, though 



