240 Browne . — The Anatomy of the 
above this one the greatest downward deflexion of any of the traces was 
98 (jl and the average was 61*57 M* In the third whorl from the base the 
oblique course of the traces was hardly noticeable, the average distance in 
a vertical direction between the point of insertion of the trace on the axial 
stele and its entry into the sporangiophore being 28 ju. In Cones B and C 
the average downward deflexion of the traces of the lowest whorl was 
34 and 31 /x respectively. In the middle region of the cone the traces 
usually pass horizontally through the cortex, while towards the apex they 
traverse it in an obliquely upward direction. 
III. The Anatomy of the Cone. 
The tracheides of the cones of E. hyemale and E. giganteum are 
essentially similar to those of the other cones studied by me. Those of 
E. maximum are smaller and markedly less strongly lignified, while those 
of E . arvense are very slightly wider and have thinner walls than those of 
E. palustre , E. limosum , E. hyemale , and E. giganteum . 
In the last species the radial extent of the xylem in the cone is variable ; 
but on the whole it is greater than in the other species studied. Some- 
times the woody tissue is seven or eight cells in depth ; in the lower fully 
developed regions of the cone it is commonly five or six cells in radial 
thickness (PI. VIII, Figs. 5 and 8). When the xylem forms narrow bundles 
this causes the vascular strands to be nearly circular as seen in transverse 
sections of the axis. Both in E. giganteum and in E. hyemale unlignified 
parenchymatous cells, such as occur also in the cones of other species, are 
found. They are not, however, as numerous as in the cones of E. maximum . 
In E. hyemale the stele is comparatively wide and ovoid as seen in 
longitudinal section. In E. giganteum the cones are longer and relatively 
more slender. In this species the axis is often slightly enlarged at the 
insertion of the fertile whorls ; this local enlargement frequently affects the 
diameter of the stele, and in Cone C gives the longitudinal reconstruction 
a very jagged outline. 
In my first paper on the cones of Equisetum I pointed out that even 
a superficial glance at the reconstruction of the stele of a cone which, like 
Cone A of E. arvense , showed a well-developed vascular system, gave an 
‘ impression of nodal bands or a nodal ring of xylem, broken up in the 
internodes by meshes of parenchyma and usually broken too at the nodes 
by the persistence of one or two of these meshes’ (Browne ( 1 ), p. 670). 
These parenchymatous meshes generally arise vertically above traces that 
have departed, though at varying distances. As stated on a later page of 
the same paper (p. 699), the irregular network of strands in the cone of 
E. limosum would seem, when considered separately, to baffle interpreta- 
tion ; but ‘ considered in the light of a comparative study of the cones of 
E. palustre and E. arvense , we see that it has arisen in the phylogeny by 
