OF BUCKLEYA QUADRTALA, B. ET IT. 



3. The Cortical Part. 



In the cortex there are no such remarkable changes as arc 

 *wn in the axial part. The increment of elements here is ex- 

 ceedingly slight and at the same time as the older part of the 

 cortex is gradually torn off by the formation of corky successive 

 layers beneath, any noticeable increase in thickness is not observed. 



The parenchymatous cells, which are the only elements of the 

 secondary as well as of the primary cortex are regular both in 

 form and arrangement. No differentiation whatever occurs in the 

 same stage of development, all being similar in size, form and 

 inner structure. Compared with the cortical elements of the 

 mother-root, they are rather short. 1 ' 



In the following lines I will discuss somewhat more minutely 

 the nature of the cortical part in order to make clear its 

 functions. 



At first we will inquire whether the sieve-tube is present or 

 not. The investigation of the haustorium of various parasites in 

 this respect has cleared up their parasitic nature. Peirce 2 ' has 

 studied the structure of the haustoria of some phanerogamic 

 parasites and established the fact that sieve-tubes are present in 

 the haustorium of the CYmvolvulaeerc, Kaftlesiacejc and Balano- 

 phoracese, while in Viscum album, a green parasite, they are 

 wanting. He then drew conclusion that the former kinds of 

 parasites must depend absolutely upon their host for food, ?'. e., 

 that they obtain raw materials through the tracheid or trachea? 



1). The cortex of the root of Buckleya consists principally of parenchyma, sieve-tubes, 

 companion-cells and a ß w hast-fibres. 



2). Peirce, On the Structure of the haustoria of some Phanerogamic Parasites. Ann. 

 of Bot, Vol. VII, 1893, p. 291. 



