STRUCTURE.] EMBRYO BUDS. 177 



distinguishing species, genera, and even natural orders ; but 

 have, nevertheless, received little general attention. The 

 vernation of the Cherry (Prunus Cerasus) is conduplicate ; of 

 the Plum (Prunus domestica) convolute ; of Magnoiiads, con- 

 volute ; of Ferns and Cycads, circinate, and so on. 



Dutrochet called by the name of EMBRYO-BUDS (fig. 24.) 

 certain nodules which are commonly found in the bark of 

 the Beech, and some other trees, and which are externally 

 indicated by small tumours of the bark. According to this 

 author such bodies are at first very small and globular, lying 

 in the tissue of the bark, near its surface ; he has found some 

 not larger than a pin's head, and thinks they are born in the 

 parenchymatous tissue. " They are at first/' he says, " com- 

 pletely free, and isolated in the bark, have a peculiar bark of 

 their own, which is united with that of the parent tree, but 

 which may in the Cedar be easily distinguished by the 

 direction of its fibres. 



" The form of such nodules is variable ; sometimes they 

 are rounded, sometimes conical, &c. When in the progress 

 of development, the woody nodules born in the thickness of 

 the bark, bring their wood in contact with that of the tree 

 which bears them, the intermediate bark disappears, being 

 destroyed by the pressure to which it is subjected, and then 



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