Fig. 1. 
Puate IX. 
An older haustorium fixed on Argyreia speciosa. The vascular 
system has undergone considerable growth in thickness. Note 
the place where most thickening takes place (x), just below 
the interrupted zone. The bundle from the mother root 
(mr.) is seen, as also its two divisions in the transitional 
region. A dark yellow mass (6) marks the upper limit of the 
nucleus. The cambium in the axis, while forming little 
secondary wood, has given rise to a series of rows of cells (a) 
simulating a secondary cortex. Some of these cells are en- 
larged at a and do not at all present the appearance of bast. 
The inner cortex is charged with calcium carbonate crystals 
(cr) and the collapsed layers (c./.) are small and converge 
downwards. 
Figs. 2 and 3. Thyloses from an invaded root of Vernonia travancorica 
showing calcium oxalate crystals and thick-walled, pitted 
cells inside them. 
Fig. 4 A thylose from the same root of Argyreia speciosa with thickened 
and pitted cells inside it. 
Fig. 5. A very old haustorium attached to a root of Cansjera Rheedii, cut in 
the middle and therefore appearing to be more regular than 
most (see figs. 4-7 of Plate I, where haustoria of the same 
age are shown). The haustorium now consists practically of 
only the vascular system. The root attached has been broken 
up and the point of attachment is minute. The collapsed 
layers (c.l.) are still visible but quite inconspicuous: they are 
so far disturbed by the secondary growth in thickness that 
they are almost in the same horizontal line. Masses of calcium 
carbonate crystals (cr) are found in both inner and outer 
cortex, the whole of this tissue now assuming the appearance 
of bark. The secondary cortex (co?), formed by the cambium 
outwards, is broad and clear of contents. The greatest 
development of the xylem is in the upper part of the vascular 
loop (a) and this dominates the form of the haustorium which 
is now turbinate. The interrupted zone (¢.z.) is bridged over 
by about forty strands of decomposed vessels. The upper 
end of the nucleus (m) is still discernible and the cells of the 
ground tissue above it are charged with crystals. 
b 
