228 Groom —On Disc India rafflesiana (Wall.). 
water in the pitchers. This extensive development and 
copious branching of the root in a pitcher with solid contents 
can only be explained either on the basis of Nobbe’s experi- 
ments proving that roots branch more abundantly in nutritious 
soils : or by supposing that, for some reason, the earthy 
particles had been conveyed to the regions in which the roots 
had been already more extensively developed. This latter 
alternative cannot at once be dismissed as absurd, as will be 
seen when the source of the particles is considered : but it is 
negatived by the observation that root-hairs are short in the 
empty pitchers, but large and persistent in the presence of the 
solid substances. Thus there can be no doubt that the 
pitcher-roots utilize the masses of earthy substance and 
organic matter found in the pitchers. Even when rain does 
not fall into the latter, the hygroscopic contents acquire water 
from the damp air and from the moisture which, as shown by 
Treub, collects even in pitchers which rain-water cannot 
reach ; and is doubtless largely derived from the aqueous 
vapour transpired through the stomata of the epidermis lining 
the cavity of the pitcher. 
At first sight it appears a matter of some difficulty for 
rain-water to get into pitchers unless their mouths are directed 
upwards and exposed to the rain, and I subsequently made 
some experiments on alcohol-material in order to see if rain- 
water can enter pitchers which are in some other position. 
I selected a not uncommon position of the pitchers for the 
purpose, i. e. the mouth of the pitcher was directed towards 
the supporting stem and pressed close against it ; the position, 
in fact, which the pitchers would always assume did they 
retain their phylogenetically original arrangement. To 
produce the effect of a heavy tropical rain on a lightly-foliaged 
tree, water was poured from the rose of a watering-can 
directly on to the trunk or branch against which the pitcher 
was held. The pitcher chosen was one which had when living 
been naturally pressed against the bark of the host-tree to 
such an extent that it was flattened around the lips of the 
mouth. In the experiments the pitcher was held in its natural 
