( Intraxylary ) Phloem in the Stems of Dicotyledons . /. 583 
The peduncle has nothing of interest in its structure. 
Fig. 5. Ecballium Elaterium. Transverse section of stem-base showing the independent 
‘ internal-phloem ’ bundles, iph, ‘ internal phloem \ x n. 
Trichosanthes anguina. 
Stem . 
Two of the bundles of the inner of the two rings or series have 
no internal phloem at all, nor do they possess protoxylem, so that they 
may represent secondary structures. 
Peduncle of Fruit . 
In the inner fleshy rind of the fruit are great numbers of small 
variously-orientated and constructed bundles, many of which are devoid of 
xylem. At a lower level, i. e. in the upper part of the peduncle, the vascular 
system consists of two rings or series of normal bicollateral bundles, and 
within these, in the pith, are a few bundles representing those above 
mentioned, which have descended from the inner rind of the fruit. One of 
these medullary bundles consists of a rounded phloem-strand with xylem 
elements situated at intervals round the greater part of its periphery; 
another had a little xylem on its outer side, apparently formed by a cam¬ 
bium ; others consisted of phloem only. At a lower level in the peduncle 
all these medullary bundles or phloem-groups unite with the internal- 
phloem strands of the bundles of the inner ring; at a still lower level one 
of these internal-phloem strands apparently had several xylem elements in 
its midst, due to its fusion with a medullary bundle. 
If we regard the structure as traced upwards from the base, we see the 
internal-phloem strands of the inner ring of bundles branching and giving 
rise to independent phloem-strands or vascular bundles, as the case may be, 
which constitute a distinct medullary system; the xylem of the vascular 
bundles which arise in this way is apparently differentiated either, as in the 
above instance, before the bundle leaves the internal phloem-strand or 
at a later period. 
The above-described structure of the peduncle is an interesting one, for, 
Qq 
