57 
in the pith of Manihot Glaziovii . 
At the nodes the various groups are connected by tangential 
branches through about half the circumference of the pith, 
on the side of the stem adjacent to the insertion of the leaf 
(Fig. 5) ; the remaining groups are not usually connected by 
tangential branches. Sometimes however, in moderately 
young nodes, one finds tubes scattered through the whole 
of the pith, sending transverse branches in various directions. 
Unlike what is the case in certain of the Euphorbiaceae, 
with non-articulated tubes 1 , no branches were observed pass- 
ing through the medullary rays and connecting the medullary 
and cortical systems. It appears therefore that there is no 
communication between these two systems in the inter- 
nodes. 
At the nodes, however, branches of the medullary tubes of 
the stem pass outwards with the leaf-bundles, and on reaching 
the cortex branch freely, forming a complicated network, so 
that it is difficult to distinguish between these vessels and 
those of the cortical systems. In one case, however, a con- 
nection was clearly observed between one of these branches 
and a tube passing upwards through the phloem of the next 
internode (Fig. 6). In transverse sections through the 
same region, radial connections were also observed between 
members of the various zones of the primary and secondary 
phloem. 
Thus it is probable that at the nodes all the laticiferous 
systems stand in radial connection with one another 2 3 . It is 
interesting to notice the close resemblance between this con- 
nection of the medullary vessels with those of the cortex and 
that in Euphorbia Lathyris z , whose non-articulated tubes 
differ so widely in their origin from those of Manihot. 
Jatropha multifida also has medullary tubes (non-articulated), 
branches from which were observed passing out with the leaf- 
1 De Bary, 1 . c., p. 437. 
2 This differs from the arrangement in the intemodes, where ‘ anastomoses in 
the radial direction were not observed either in the primary or secondary phloem.’ 
Scott in Quart. Journ. Microscop. Science, vol. xxiv. p. 197. 
3 De Bary, 1 . c., p. 438, Diagram. 
