505 
Pedicular is vulgaris , Tournef. 
of the { nucleus ’, and those c.c . of the 
cortex, and the difference in density 
of their protoplasmic contents are 
shown. The cells of the tracheidal 
plate t.p. are in all stages of differen- 
tiation ; some still have completely 
unthickened walls, whilst others have 
become lignified to a considerable 
extent. The strand of tracheidal cells 
t.c. connecting the thickened tracheidal 
cell p.t. of the penetrating piliferous 
layer with the elements of the tra- 
cheidal plate is not complete owing to 
the fact that the section was cut in a 
slightly oblique direction. The black 
line d.r . represents the crushed remains 
of the cortical tissue of the host root. 
Fig. 3, c, h. i represents a median 
longitudinal section of a haustorium, 
cut in such a plane that a transverse 
section of the mother root, from which 
the haustorium arises, is obtained. In 
this plane the central mass of small- 
celled tissue is seen to be surrounded 
only by a very few layers of cortical 
cells, c.c., and nearly all the cells of 
this central mass have become lignified 
D 
