172 



Fr. J. Mathiesen. 



also the case in the primary root. As the root gets older, 

 the vessels increase in number, the epidermis dies away, 

 after which the cortical cpIIs become emptied of starch and 

 finally perish. Crystals of a calcium salt, sing'e as well as 

 aggregate, are found in the bark, especially in the exodermis 

 of the older roots. 



The Rhizome. A transverse section through the lower 

 part of this shows the severed adventitious roots and the 



Fig. 3. Primula egaliksensis. 

 A, Tranverse section of the primary root (Seedling from the Botanical Garden, Copen- 

 hagen) ; (Obj. 4, Oc. 4). B, Transverse section of a young adventitious root, showing the 

 central cylinder and the inner layers of the primary cortex; E, Endodermis with Casparian 

 spots; (Obj. 4, Oc. 6). (Igaliko.) 



vascular strands of the leaves, also a central group of 2 — 4 

 vascular bundles. Towards the upper end of the rhizome, 

 where this passes over into the terminal peduncle, the number 

 of the vascular bundles increases, but with a reduction in 

 the size of each bundle, and at the same time several layers 

 of the surrounding parenchyma devdop into a continous 

 sclerenchymaring. The vascular bundles differ from the nor- 

 mal and approximate to the hadro-centric type with sieve- 

 tissue closing more or less distinct'y round the inner side of 

 the bundle; exceptions to this are seen in the bundles at the 



