THE FIBRES, &C. 59 



bears the name of Layer, (stratunu) The layers are 

 generally concentric rings, or cones, placed one upon 

 another ; they are far from being simple organs, since 

 they are formed not only of fibres, which are themselves 

 compound, but also of cellular tissue more or less abun- 

 dant, which separates and connects, either the fibres of 

 the same layer, or the layers themselves. I shall return 

 to the Woody and Cortical Layers, in speaking of Stems ; 

 and I only mention them here to avoid confounding them 

 with the elementary organs. 



