432 Browne . — A Fourth Contribution to our Knowledge of 
the basal whorl of sporangiophores — might well seem to belong to the first 
internode of the cone proper. Judging, however, from their superposition 
to the axial strands below the annulus, from their alternation with and from 
their origin slightly below the sporangiophores, these two meshes would 
seem to be of the same nature as those between the ninth and tenth and the 
thirteenth and fourteenth traces of the same whorl, the supra-annular 
origin of which is more obvious. The elongation of the axis between the 
annulus and the basal whorl of Cone B allows of a clear distinction between 
the supra-annular meshes and those arising within the cone proper. In 
Cone C this region was not sectioned. 
As in all the other cones studied by me some parenchymatous meshes 
that originate below the sporangiophores persist into the cone. These will 
be considered later on. Excluding them, the following table summarizes 
the number and nature of the meshes found in Cones A, B, and C of 
E. sylvaticum : 
Cone, 
1st 
2nd 
. $rd 
4 th 
5 th 
6 th 
7 th 
8 th 
9 th 
Total 
order. 
order. 
order. 
order. 
order. 
order. 
order. 
order. 
order. 
meshes. 
A. 
17 
13 
9 
6 
4 
1 
0 
0 
1 
5 i 
B. 
10 
13 
2 
2 
0 
2 
1 
0 
0 
30 
C. 
1 1 
7 
6 
6 
5 
5 
0 
0 
0 
40 
38 
33 
17 
14 
9 
8 
1 
0 
1 
1 2 T 
As pointed out in a previous paper (Browne ( 2 ), p. 233), meshes of the 
same order may arise or be closed at very different levels in the internode. 
Thus, apart from the factor of the different lengths of ititernodes, meshes of 
the same order may vary appreciably in height, even in the same internode. 
In E. sylvaticum some of the meshes are closed by the formation of additional 
xylem in the neighbourhood of the node. In other cases the closure 
is effected by the oblique course of one or both branches of a strand, 
this oblique course leading a little higher up to fusion with another strand 
or branch of a strand. In such a case the mesh is only closed somewhat 
above the level of the departing trace and of the initiation of the new mesh 
arising by the forking of the strand. But, as in my previous papers, I have 
not considered the mesh thus closed as of a higher order than those closed 
at or below the node. Though the axes of Cones A, C, and D of E. debile 
have not all elongated fully, the appearance of the tissues made it clear that 
the differentiation of the metaxylem had been completed. On the other 
hand, neither Cone B nor Cone E of this species was mature. The develop- 
ment of the spores had not been completed, and in the cells of the sporan- 
gial wall the characteristic thickenings had not yet made their appearance. 
In both these cones the phloem projected beyond the xylem over a con- 
siderable vertical extent, in Cone E throughout most of the cone. To 
judge from mature cones, in which the metaxylem always extends later- 
ally as far as and sometimes a little farther than the phloem, the full 
