Rosaceæ. 25 



mm.) it becomes a spacious reservoir of food-material. A 

 plant collected on Snenæs in the middle of June contained 

 in the primary root in addition to some starch large quantities 

 of fat. The walls in the older secondary cortex are collen- 

 chymatous and the tissue has the appearance of being highly 

 compressed. — The periderm around the roots does not attain 

 any considerable thickness (about 10 layers) and consists of 

 alternating layers of cork and phelloid. Small intercellular 

 spaces occur between the phelloid-cells, but there are pro- 

 bably none upon the inner side of the cork-layers. 



The structure of the rhizome is similar to that of the 

 primary root, the vessels being gathered into rays rich in 

 parenchyma and separated by broad non-lignified medullary 

 rays (Fig. 9, G.). Distinct annual rings were not observed 

 either in the rhizome or in the primary root. The pith is 

 large and persistent; it contains large intercellular spaces. 

 The secondary cortex becomes compressed by the growth in 

 thickness; the walls are somewhat collenchymatous. In the 

 young rhizome there is an endodermis. The periderm con- 

 sists of layers of cork and phelloid-cells which alternate; it 

 does not attain any considerable size (about 8 layers). Inter- 

 cellular spaces occur as in the root. In a rhizome collected 

 on July 12 on Snenæs (N. E. Greenland) in addition to some 

 small-grained starch a considerable amount of fat was found 

 in all the living tissues. 



The flower-stalk contains about 10 vascular bundles; 

 no continuous cambium is developed. There is no endo- 

 dermis proper. In the older stalk the several-layered peri- 

 cycle is probably transformed into bast; but my material 

 contained young stalks only. The few-layered cortex con- 

 sists of an inner part with large cells without chlorophyll 

 and an outer part with chlorophyll; in the latter the outer- 

 most cell-layer is slightly collenchymatous. The outer wall 

 of the epidermis is about 3p thick. The pith is homogeneous. 



