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Browne. — The Anatomy of the 
of E. limosum (Browne ( 1 ), p. 677), and between the thirteenth and four- 
teenth traces of the fourth whorl of Cone B of E. maximum (Browne (2), 
PL XIII) would convert single meshes, narrowed at a node, into two meshes 
of lower orders. The cases quoted are merely examples and do not con- 
stitute a list of the cases in which this phenomenon can be observed, and the 
reader who studies my reconstructions of the steles of cones will be able to 
find plenty of other examples. I have already pointed out that, owing to 
this correlation between the closure and origin of meshes and the amount of 
axial xylem at a node, the proportion that the number of meshes bears to 
the number of sporangiophores affords a general indication of the compara- 
tive reduction or good development of the vascular tissues of the cone. 
The smaller the proportion of meshes compared with the number of sporan- 
giophores the greater the reduction of the xylem (Browne ( 2 ), p. 236). 
This, however, is only true without further modification of the cones of 
E. arvense , E. hyemale , and E. palustre , in which the meshes are closed, 
generally speaking, by the formation of additional tracheides at the nodes. 
In E. giganteum , E. maximum , and E. limosum , some of the meshes are 
closed in this way ; but, commonly in E. maximum and in E. limosum and 
more rarely in E. giganteum , meshes are closed also by the obliquely 
divergent course of some of the tracheides just above the node. When the 
nodal xylem is relatively well developed a trace-bearing strand, though not 
wide enough to unite with neighbouring strands, is still wide enough to give 
off a median trace, above which a fresh mesh arises. In such cases the 
closure of the mesh of the internode below is often affected by the obliquely 
upward course of one of the branches (into which the appearance of the new 
mesh has divided the trace-bearing strand) and its fusion with the adjacent 
strand or branch of a strand. If both branches of a trace-bearing strand 
fuse with neighbouring bundles the meshes lying on either side of the 
strand in the internode below are closed. When the nodal xylem is even 
more reduced and a trace departs from an isolated strand, too narrow for 
the formation of a fresh mesh above such a trace, the unbranched strand 
may close one of the meshes of the internode below by its oblique course 
and ultimate fusion with a neighbouring bundle. The closure of a mesh by 
the fusion of two such narrow, unbranched strands is especially characteristic 
of nodes above which reduction in the number of members in a whorl and 
of internodal strands is about to occur, for example of the apices of cones. 
Not uncommonly, in all cones, a mesh is closed partly by the formation of 
additional tracheides at the edge of one of the strands bordering on a mesh, 
and partly by the oblique course of the tracheides of the bundle, or branch 
of a bundle, on its other side. Where the closure of a mesh is due to the 
oblique course of the tracheides above a node the closure is naturally only 
effected above — sometimes slightly, sometimes considerably above — the 
node. Where the fusion of the strands occurs but little above the node, 
