THE DISEASES OF PLANTS. 305 



go deeper into the wood than the external layer, which 

 being the last formed, is the most tender. 



Emily. Then it cannot be so difficult to root out a 

 misletoe, as I have heard ? 



Mrs. B. You must recollect, that every year a new 

 layer of wood grows over the root ; so that without having, 

 itself, penetrated further, it becomes annually buried deep- 

 er ; and after some year's growth in so hard and compact 

 a soil, that there is but little chance of being able to ex- 

 tract it. without wounding the branch beyond recovery ; 

 the only mode of effectually extirpating it, is to cut off the 

 branch to which it is suspended ; it is better to lose that, 

 than to suffer the tree to be molested by so disagreeable 

 a companion. 



The misletoe is more partial to some species of trees 

 than to others ; but the oak is the only one almost wholly 

 exempt from its depredations. 



Caroline. I thought that the misletoe attached itself 

 to the oak in preference to all other trees, and that the 

 Druids considered their union as sacred. 



Mrs. B. It was probably owing to its so seldom attack- 

 ing this tree, that the Druids held it in such high veneration 

 when they found it there. This tree has, however, another 

 enemy, of a very similar description, called the Laurientius, 

 which confines its ravages to this sovereign of the forest. 



The Cuscuta, commonly called Dodder, is a parasite, 

 which attacks lucerne, trefoil, and several of the artificial 

 grasses : it has neither cotyledons nor leaves, consisting 

 simply of a sort of filament or stalk, which, after it has 

 sprouted, falls and perishes, when it finds no plant to 

 which it can adhere ; but if it meets with any of the artifi- 

 cial grasses, it fastens upon them, and feeds upon their 

 juices. The seeds sometimes germinate in the soil, and 

 sometimes on the artificial grass itself. The mode of de- 

 stroying this noxious parasite, is either to burn or to mow 

 the artificial grass very frequently, in order to prevent the 

 seed of the Cuscuta from germinating ; or else to change 

 the course of cropping, and sow corn, for this parasite 

 will not attack grain, or any endogenous plant. There 



1644. How deep does the root penetrate! 1645. Why is it not 

 easy to root out a misletoel 1646. Is the misletoe common to all 

 treesl 1647. If it is not partial to the oak, why were the Druids dis- 

 posed to consider an union of them sacredl 1648. What is said of 

 the Cuscutal 1649. How does it germinate and how may it be destroyed t 



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