104 



ORGANOGRAPHY. 



in all cases where the parenchyma near the surface of a plant 

 has its vitality excited, or when an accumulation of nutritive 



Fig. 195. 



Fiy. 196. 



Fig. 195. Leaf of DryophyUum caJycimim with buds on its margin 



Fig. 196. End of the leaf, I, of Mala,ris jmludosa, with buds, h,b, on its 



margin Fig. 197. A portion of the leaf, /, of Oruithvgalum thyrsm- 



deuni, showing buds, b, b, b, on its surface. 



matter takes place, it is capable of taking up an independent 

 development, and forming adventitious biufs. These buds differ 

 however from those commonly produced in the axil of leaves, 

 or at least from those which remain dormant during the winter ; 

 thus they are smaller, and have no external protective organs 

 _ or scales. 



^'V- 199. EmbryoDuds.^ln 



some trees these ad- 

 ventitious buds, in- 

 stead of being deve- 

 loped on the outside of 

 tlie stem, are enclosed 

 in the bark. Such have 

 been called embryo- 

 buds or nodules. They 

 may be readily ob- 

 served in tlic bark 

 of certain trees, such 

 as the Cork-oak, the 

 which they ])roduce 

 examined, are found 



Fig. 198. Embryo-bud or nodule of ithe Cedar. 



Fig. 199. A vertical section of the same 



surrounded by the bark. 



Beech, tlie Cedar of Lebanon, &c., in 

 externally little swellings, which, when 

 to be owing to the presence of these nodules, which have a 



