46 
DESCRIPTION OF PLATES. 
cork formed in the host’s root round the edge of each lobe of 
the sucker, and the continued formation of wood in the part of 
the cylinder thus protected. 
Figs. 2 and 3. Diagrams of Olaa scandens haustoria in the gland 
stage and after penetration. c./., collapsed layer. The dotted 
line signifies the outline of the nucleus m. gil, remains of a 
gland. 
Figs. 4 and 5, A similar pair of diagrams for Santalum albwm. 
Figs. 6 to 10. Diagrams of successive stages of secondary thickening 
PrarTe XX. — 
in the haustorium. The darker, inner portion signifies older 
vessels breaking down and resembling duramen, although this 
layer is not usually pronounced. 
Fig. 1. An old, moribund haustorium fixed on a root of Casuarina equiseti- 
folia, for a description of which see the text (paragraph 16). 
Fig. 2. The end of a sucker lobe in a haustorium fixed on a root of 
Jasminum sessiliflorwm. The sucker cells are seen to spread 
out in a mass of dark brown substance which bathes the 
tissues of the host. The colouring matter is probably develop- 
ed from the host, but the bulk of the matrix is secretion. 
Note the latest addition from the secreting cells as a clear 
border outside the ends of some of the cells. 
small portion of the vascular strand of the axis of the 
haustorium with secondary thickening taking place. The 
vessels are uniform and bear from two to three rows of pits. 
The cambium passes outwards almost directly into the irregular 
parenchyma and there is no trace of bast formed from it. 
Note the circular perforations of the vessels where they meet one 
Fig. 4, a—f. 
Pirate XI.— 
another, 
A series of drawings of the fibro-crystal masses such as are 
seen cut across in various directions at the top of fig. 1. Fig. 4 a 
is taken from a transverse section of a young root of Olax 
scandens. 
Self-attached haustoria of Olax scandens (see the text, paragraph 18). 
Fig. |. Shows such an attachment under low power. The vascular strand 
of the axis is much developed and accompanied by bast (as 
indicated by the fibro-crystal masses and the medullary rays) 
right down to the end of the sucker. At the latter point the 
xylem, cambium and phléem are seen to be in direct continua- 
tion of those of the host’s root. 
