OF BUCKXEYA QUADRIALA, B. ET IT. 15 



strand is composed of a complete ring of vessels. But in a section 

 passing through the median portion of the haustorium, wo sec 

 that the vessels are divided into two opposing masses (e), giving 

 an elliptical outline to the axial part. We find here some notches 

 in its contour which becomes deeper as we go down to the next 

 section. Each vascular strand dissolves away finally into a certain 

 number of vessel-groups (/), and in the cross-section passing 

 through the apical region of the haustorium we will observe that 

 these vessel-groups are represented in longitudinal section with 

 their ends frayed into brushes, indicating thereby that they run 

 transversally in this region {g). 



Occasionally we find in the pith strands of vessels or in 

 other cases numerous strings of isolated vessels (Fig. 19 iv), 

 traversing it longitudinally. Sometimes in their course they unite 

 with the main strand and sometimes disappear amidst the pith. 



At the front of the haustorium the central part is dis- 

 tinguished from the surrounding attaching-folds by its projecting 

 into the host, and is therefore to be called the sucker as in the 

 haustoria of other Santalacete. The sucker consists mainly of the 

 axial part with a few layers of cortical parenchyma around it. 

 There are no other particular characteristics to lie noted, except 

 that the constituent cells are somewhat elongated. It suffices to 

 state here that the apical layer of parenchyma in the sucker, 

 which, being free from coating of the corky layer, can be in 

 direct contact with the host, exhibits the structure of the so-called 

 absorbing tissue, i. e., it is palisade-like, rich in granular plasm, 

 and is furnished with a very thin wall and large round nuclei. 



When we take into consideration this histological similarity 

 of the sucker to the main part of the haustorium, and again 



