Latex and its Functions. 
209 
of this laticiferous system in a seed, which has nearly reached 
its full size, but which is still far from maturity. A sheath, 
as it were, of laticiferous tissue forms around the nucellus, 
extending right from the chalaza to within a short distance 
from the micropyle. This is marked in thick irregular lines 
in the figures, one of which represents a median longitudinal, 
and the other a transverse section of the young seed. 
The Hevea trees in the Peradeniya Gardens from which 
the material was collected, flower during April. Some cap¬ 
sules taken on May 5, which had grown to the size of 
large peas, showed no sign of this laticiferous system in the 
inner integument. The system at this early stage had not 
commenced to be differentiated. 
A second lot obtained on May 13, with young seeds 
5 to 6 millimetres long, revealed the commencement of this 
laticiferous system. Groups of parenchymatous cells situated, 
as a rule, about one or two rows of cells external to the inner 
limiting layer of the inner integument, increase considerably in 
size—to four or five times that of the neighbouring cells. Their 
walls thicken somewhat and their contents assume a more 
coarsely granular condition (Fig. 4). These, the laticiferous 
cells, appear first about the chalaza and develop more rapidly 
in the half of the seed along which the raphe runs ; indeed the 
production seems finally to be greater in this half than in the 
other. The walls between groups or rows of these cells partially 
break down, and processes grow out from many of them. 
At a later stage (middle of June) this laticiferous system 
had reached about its full development. The processes are 
now a conspicuous part of the system ; they branch a little. 
When a young seed at this stage is cut across, latex oozes 
out around the nucellus, or rather around the developing 
endosperm, since the former is now much crushed. 
This laticiferous system then of the inner integument con¬ 
sists of a number of cells communicating one with another, 
due to the partial dissolution of the intervening walls, and 
of unsegmented processes emitted from these cells (Figs. 
5 and 6). Such a laticiferous system suggests a blending 
