416 



Fr. J. Mathiesen. 



nished, had a xylem-cylinder, 3 mm thick, which consisted 



for the most part of vessels, thin-walled and rather wide; 



in addition thin-walled wood-fibres occurred. 



Parenchyma rays did not occur, neither were there any 



indication of growth-zones. In the secondary cortex sieve- 

 tubes were rather 



scantily present. 

 Cork was not devel- 

 oped. In the roots 

 both the endoder- 

 mal and the exor- 

 dermal cells were 

 full of a brown sub- 

 stance. 



The Stem. In 

 Hovelaque's work 

 it is particularly the 

 anatomy of the stem 

 which has been ex- 

 haustively treated, 

 and Bartschia has, 

 on this point, since 

 been again investig- 

 ated by HOLLSTEIN. 



To this I have noth- 

 ing new to add, and can therefore confine myself to the fol- 

 lowing brief description. 



A section taken from a little above the middle of the 

 foliage-leaf-bearing part of the stem (a diagrammatic repre- 

 sentation is given in Fig. 17, C) shows a thin-walled epider- 

 mis, beneath which there is a cortex, the outermost layer of 

 which has somewhat thickened cell-walls; several of the cor- 

 tical cells have undergone division by means of thin radial 



Fig. 17. Bartschia alpina. 

 Diagrammatic transverse sections of the stem : 

 A and B, from runners; C, from tlie aerial 

 stem taken between the 3rd and 4th pair of 

 foliage-leaves; D, taken at the point of tran- 

 sition between rhizome and the aerial stem 

 (the black ring in С and D is the hard-bast, 

 whilst the wood-ring in all the figures is radi- 

 ally shaded). (About i%.) 



