( Intraxylary) Phloem in the Stems of Dicotyledons. /. 579 
as a rule, near the periphery of the stem, just as in Monocotyledons, limits 
as is the case in this class, the central cylinder. 
In this species we thus discover in the stem the existence of vestigial 
remains of outer series of bundles pertaining to the original scattered 
system ; in the last species we found the vestiges of an inner series of 
bundles belonging to the same scattered system. 
Cucumis sativus. 
Stem. 
As far down as a few millimetres or so below the point at which 
the green portion of the stem terminates the structure offers nothing 
of particular interest. But at about that level, where the stem has become 
very deeply lobed and fluted into six columns, each of which is traversed 
by a bundle, the majority of these bundles has each, in place of the ordinary 
internal-phloem strand, an inverted vascular bundle} often more than half its 
own size, a large amount of xylem being present, including vessels and 
fibres. 
In another stem the external phloem is connected with the internal by 
‘ commissural strands ’ which also often have a cambium and a few xylem 
elements formed at the flanks of the xylem of the main bundle ; this latter 
is often quite surrounded by phloem. 
It is thus in the lower part of the stem only that the internal-phloem 
strand is represented by a vascular bundle. 
C. echinophorus. 
Petiole. 
In the typical region, where the groove occurs on the upper side, 
is a complete circle of bundles ; but those on the median upper side opposite 
the groove are rudimentary, having one or two or no xylem elements and 
a small amount of phloem; two, at any rate, are represented by small 
phloem-strands only. One of the bundles near the end of what (when the 
ventral bundles have died out lower down) will become the arc has several 
xylem elements developed on the outer side of the internal phloem, forming 
a quite distinct and individualized inverted bundle. 
Cucumis Melo. 
Peduncle of Fruit. 
The double series of bundles is practically constituted as a single ring. 
A few of the bundles have two internal-phloem strands, one behind the 
Other in the same radial line ; in one case the extra (innermost) strand 
1 Solereder makes no mention of this. 
