492 Fr. J. Mathiesen. 



peripheral cells of the pith, does not appear to take place 

 until towards the time of ripening of the fruit. 



The Leaf: Some of the cells of the upper and lower 

 epidermis are shown in surface view in Fig. 46, В and C. 

 Here, the great thickenings on the lateral walls of some of 

 the epidermal cells of the upper surface and, as regards the 

 lower surface, especially the walls of the cells which bear 

 the glandular hairs, is very striking. This feature, however, 

 is not constant in the species; as regards this point the 

 individuals from Dovre were, on the whole, as shown in the 

 figures in question, but the thickenings were far fainter, or 

 even entirely wanting, in the specimens from Rorås. As 

 usual in the Pediciilaris spp. the stomata occur only on the 

 lower surface of the leaf, and the epidermal cells which 

 surround them have highly undulating lateral walls. 



A transverse section of the leaf is shown in Fig. 46, A. 

 The spongy parenchyma consists of copiously-branched cells, 

 especially in its lower layer. As seen in the figure, the epi- 

 dermis of the lower surface, in the spaces between the branches 

 of the veins, is highly convex and in places without direct 

 connection with the spongy parenchyma, so that, on the 

 lower surface of the leaf, there are hollow spaces — air- 

 chambers — in the roof of which the stomata occur. In 

 the figure, a glandular hair is seen under each of the veins; 

 two such hairs are shown in surface view in Fig. 46, C. D is 

 a non-glandular hair. Chlorophyll-grains occur abundantly 

 in the whole of the mesophyll, and in the epidermis of the 

 lower surface. 



A section through one of the scars which the leaves at 

 their fall leave on the rhizome, showed that here a cork of at 

 least six layers was formed; outside the leaf-scars no cork- 

 formation takes place. A small portion of such a section is 

 shown in Fig. 45, B. 



