Mr Barber, Parasitic Trees in Southern India. 255 
tissue is developed in the centre, which may be of the nature of a 
water reservoir : there is no trace of the interrupted zone in the 
vascular system: there is a single, median plate of vessels instead 
of two parallel ones, and there is consequently no pith in the 
axis of the haustorium : the sucker consists entirely of nuclear 
tissue (cf. Plates II. figs. 6 and 6 a, and III. fig. 13). 
Ximenia americana agrees in certain respects with Olax scan- 
dens but differs in others. It has not as yet been sufficiently 
studied. Calcium oxalate crystals are present: the collapsed layers 
end as in Olax ; there are two bands of vessels in the axis of the 
haustorium : there are indications of the clear tissue as in Olax : 
the cortical folds completely envelope the root attacked and the 
haustoria attain to a very large size, reaching a square inch in 
surface area in the specimens collected (cf. Plates II. figs. 5 and 5a, 
and III. fig. 14). 
The study of the haustoria of Santaluni album and Olax 
scandens is completed and will be published in due course. That 
of the remaining species collected in South India is proceeding. 
Description of Plates. 
Plate I. A small branch of Santalum album with the first 
appearance of “ spike.” The middle twig is normal and, as it is 
fruiting, it is resting from leaf-formation. The side branches, at 
first normal, are passing into the small-leaf condition. It is easy 
to mark the exact spot where the spiked condition has commenced. 
Not only are the leaves smaller but they are much closer together 
and the internodes are shorter. From the latter character it is always 
easy to tell when a tree has died of spike. 
Plate II. Diagrams of the haustorial glands of (1) Santalum 
album , (2) Osyris arborea, (3) Thesium Wightianum, (4) Opilia amentacea, 
(5) Ximenia americana, and (6) Olax scandens. 
The first four are more or less similar and the lumen in young 
glands, as shown in 1 a, is traversed by the faint outlines of the upper 
part of the secreting cells. 
In 5 and 6 the fate of the secreting cells is different and the lumen, 
in very young glands (5 a and G a), is traversed by rows of cells which 
are becoming disintegrated and, ultimately, disappear entirely. The 
two latter, members of the Olaceae, thus differ from the Santalaceae 
(1 — 3), and Opilieae (4) in that the glands are schizogenous instead of 
lysigenous. 
