14 AKT. 10. — S. KUSANO : STUDIES ON THE PARASITISM 



irregular ; besides they are short and have an oblique terminal 

 wall. Otherwise the vessels are regular, much elongated and have 

 slightly oblique terminal walls. The center of the bottom of the 

 vascular strand or properly of the axial part being composed 

 mainly, besides vessels, of parenchyma does not look so dense as 

 in the other parts (Fig. 19 c, d). When the frontal extremity of 

 the strand bends much towards its lateral side (Fig. 10), evidently 

 on account of the pressure exerted by the host-root, the arrange- 

 ment of the elements at that part will be greatly disturbed, the 

 vessels being much shortened into a rhombic form (the same 

 change takes place at the same time in the cortical elements, 

 which directly surround the strand). In general, at the frontal 

 end of the strand the vessels are divided into numerous bundles, 

 of which only a few vessels abut directly on the wood of the 

 host, while others seem to disappear among the parenchyma (Figs. 

 7, 19). It should be noticed that the ends of these bundles of 

 vessels are directed mostly towards the lateral side in order to 

 abut on the radial wall of the woody elements of the host, which 

 have been produced since the haustorium attached to the woody 

 part of the former. 



In order to obtain a more definite idea of the form of the 

 axial part and of the structure of the vascular strands, it is 

 advisable to consult serial cross-sections passing through several 

 points of a haustorium, as shown in Fig. 19. At first, the section 

 through the bottom of the flask (c) shows that the axial part is 

 roundish and that vessels are densely arranged at its periphery 

 but scattered in its center. At a little higher level the section 

 is similar in form with a similar arrangement of vessels, but 

 if is somewhat laterally compressed (<(). It is thus clearly seen 

 from these two figures that the basal portion of the vascular 



