Stem of Angiopteris evecta . 507 
roots represented in Fig. 1 have an upward direction, but 
this is due to the action of an artificial pressure. 
We will turn now to the consideration of the leaf-trace 
bundles. These come entirely from the outermost zone of 
vascular tissue, and in this point the stem now described 
appears to differ from that examined by Mettenius, who clearly 
states that in his plant the leaves are supplied with strands 
coming from the second as well as from the outer zone 1 . 
As can be seen from Figs. 5 and 6, the number and arrange¬ 
ment of leaf-strands vary considerably 1 ; it would perhaps 
convey the truest idea of the arrangement to say that a 
meshed segment of the outermost zone passes off into a leaf. 
The difference in character of the vascular tissue on the 
under and upper side of the stem necessitates a different 
arrangement of the leaf-trace bundles in the two cases. The 
meshes formed by the strands in the leaf-bases on the under 
side of the stem are long and narrow, and in consequence 
of this the strands themselves do not anastomose so frequently. 
In Fig. 6 leaf A may be taken as typical of this arrangement, 
and in Fig. 5 leaf I represents the most general form of the 
leaf-trace bundles on the upper side of the stem. 
Leaving for the future the more detailed account of the 
foliar strands, we turn to the consideration of the vascular 
tissue in the inner zones of the stem. 
The gap in the outermost zone occasioned by the departure 
of the leaf-trace bundles is filled up by a segment coming from 
the next inner zone. This is shown in Fig. 5, where the gap 
in the superficial zone of vascular tissue, formed by the 
departure of four strands to leaf I, is filled up by a meshed 
segment rising from the second zone. The gradual passage 
outwards of this compensating segment from the inner to the 
outer zone is shown, in the drawing, by a diminution in the 
degree of shading; the points of union of the two zones are 
shown at A, B, C, D. 
The compensating segment unites right and left of the 
leaf-base with the outermost zone, and, after continuing for 
1 Mettenius (’64), p. 512 . 
