( Intraxylary ) Phloem in the Stems of Dicotyledons. /. 575 
and to each other. The wide rays are filled with separate phloem-strands. 
The internal-phloem groups also give off smaller branches, pursuing a very 
irregular twisting course, into the pith , where small phloe7n-gro2ips are seen 
to occur ; some of these latter possess, at least during part of their course, 
xylem . 
This structure of the node is not a haphazard one. The node is 
the most conservative portion of the vegetative stem. In the absence 
of any convincing proof of the presence of a physiological cause to account 
for the supernumerary medullary phloem-strands and bundles, their 
presence may be regarded as an ancestral trait, probably representing the 
vestiges of a former medullary bundle-system. The fact that they belong 
to the same system of strands as the ordinary internal-phloem strands of 
the ring-bundles, shown by their fusions therewith, is an indication that the 
ordinary internal-phloem strands really represent independent bundles 
which have, in the majority of cases, lost their xylem through degeneration. 
Peduncle of Male Flower. 
In the upper part one or two of the bundles of the ring have 
a few primary xylem elements on the pith-side of the internal phloem, 
which, lower down, along with a little phloem, pass off as a small medullary 
bundle, whose xylem, at a still lower level, dies out. In other words, 
a phloem-strand of the pith, if traced upwards , becomes a vascular bundle, 
which, at a still higher level, fuses with the internal phloem of one of 
the ring-bundles. This phloem-strand was not traced to its conclusion 
in the lower part of the peduncle ; it probably ended blindly in the pith. 
Peduncle of Female Flower . 
In a young peduncle examined there were seven phloem-strands 
situated in the pith near the bundles of the cylinder ; they were about 
the same size as the internal-phloem strands of the latter, but quite cir¬ 
cular in shape. Some have a smaller phloem-strand lying near them ; 
these smaller strands also occur in the rays and pericycle, and are very 
numerous ; farther down they either fuse with the larger strands (internal- 
phloem groups or medullary ones) or else die out in situ. The larger 
medullary strands were not followed to their ending. Some of these latter 
have a vessel or two attached to them, chiefly on the outer side. 
In a mature peduncle bearing a fruit it was observed that in the upper 
region below the fruit occurred great numbers of small variously-orientated 
vascular bundles in the pith , nearer the margin than the centre of the 
latter, as also along the inner sides of the ring-bundles at the embouche- 
