36 ART. 10. — S. KXSANO : STUDIES ON THE PARASITISM 



bo, lie remarks that the sucker of Osyris is somewhat different 

 from that of Thesium in that its tissue is composed of unelongated 

 cells, " unmittelbare Fortsetzung derer des Haustorialkernes.' n) 

 When we take into consideration the structure of the haustorium of 

 Buckleya, it seems to me to be needless to distinguish the so-called 

 sucker from the " Kern," since the " Kern " itself must be re- 

 garded as an absorbing organ, and since, further, it is impossible 

 to find any anatomical difference whatever between the sucker 

 and the " Kern." This view r will seem quite natural when we 

 examine the haustorium which is advanced in age and possesses 

 a discoidal shape (Figs. 9, 10). 



Solms-Laubach has pointed out in Osyris that the sucker, 

 after having reached the wood of the host-root, expands along it, 

 thus lifting up the bast, and that in some cases the lateral sides 

 of the sucker are divided into finger-shaped processes, which 

 terminate in the bast with the wood of the host interposed 

 between them. 2) He thought that this is due to marginal growth, 

 but did not say whether this growth is primary or secondary ; 

 nor did he say anything about the growth of the entire haus- 

 torium, in spite uf the existence of a meristematic zone bordering 

 the vascular strand. In Buchleya I have only rarely found that 

 the sucker is divided as in Osyris. In such a case, as the end 

 of each division is applied to the bast of the host and its cells 

 elongate themselves towards the bast, each division must increase 

 its length correspondingly with the growth of the host-root. This 

 instance confirms the existence of the marginal growth of the 

 sueker in Buchleya also, but it must be considered as an abnormal 

 ease. I have also ascertained that the sucker, as soon as it meets 



1.) lue. cit. p. 556. 



'1). Compare Oil figure of Solms-Laubach (loc. cit. Tal. XXXII. Fig. 8). 



