259 



like the tissue cushions on the various deciduous bark layers, which are like 

 warts and occur in lines, were found always on the inner side of the layer 

 which was being raised up and had exactly the appearance pictured later 

 under the section "Bark Refuse" in the elm. This section should be con- 

 sulted. 



The greatest possibility of separation of the lamellae from one another 

 was found where a rotted tissue layer, i. e., in a condition of humifaction, be- 

 gan to disintegrate and formed a surface of separation. The rotted bark con- 

 sisted of cork cells, as shown on the upper side B in the accompanying cross- 

 section (Fig. 35), while H shows the bark which lay nearer the wood, and 



rp'. 



Fig. 35. Mouldy bark scale of a pine from the Liineburger moor. (Orig-.) 



therefore was younger; rp is corked^ firm bark parenchyma while k is the 

 full cork, loose bark parenchyma and t the plate cork. The bark scales were 

 therefore composed of bark parenchyma elements, which advance further 

 and further toward the fresh bark and the cambium. They are separated by 

 layers of sheet cork and become suberized. Besides this, we also find clus- 

 ters of loose cells, which are more abundant the deeper the base of the trunk 

 has stood in the moss. The spongy constitution of the underside of the dif- 

 ferent bark lamellae arises from the morbid luxuriousness of the parenchyma 

 and full-cork masses. As a result of the moisture and the scanty supply of 

 oxygen, these excrescence tissues become slimy and form the rotted bark, 

 which facilitates the separation of the lamellae. 



