238 Browne.—A Second Contribution to our Knowledge of the 
of cone. This formation of infra-nodal bands of xylem in the cone is 
a marked characteristic of E. maximum , and they must not, either, be 
confused with the relatively wide internodal strands, resulting from the 
fusion of two strands of the node below, that only give rise to a single trace 
at the next node. Such a strand may be as wide in the internode as a 
band of xylem that at the next node gives rise to two or more traces ; but the 
strand is truly single, and its origin from two whole strands results from a 
local diminution of the number of members in the upper of the two whorls, 
while the two strands composing the band, though closely fused, have not 
become truly one since they give off two traces. Relatively wide single 
strands resulting from the fusion of two whole strands occur in E. maximum , 
e. g. trace 11 of the sixth whorl and trace 7 of the seventh whorl of 
Cone A (PL XII); they are found, too, in E. limosum , e. g. trace 2 of the third 
whorl of Cone A (Browne, p. 676, Text-fig. 5). 
In the cones of the other species studied, parenchymatous meshes 
occasionally, though very rarely, originated or were closed—or in other 
words, branching or fusion of strands occurred, apparently unconnected 
with the departure of traces, or with an increase or decrease in the number 
of members of successive whorls. In Cone B these anastomoses are rather 
more numerous, which is not surprising if we remember that this cone is 
a very irregular one. 
Alternation and Superposition of the Whorls of the Cone. 
In E. maximum the alternation of the sporangiophores at the exterior 
of the cone is much less regular than in most of the species of the genus. 
Even to the naked eye considerable irregularity in the insertion of the 
sporangiophores is apparent, especially in the older and larger cones. 
Externally, Cone B afforded clear indications of the occurrence of pseudo¬ 
whorls and of the local duplication of whorls. Still, the generalization that 
the sporangiophores of successive whorls alternate with one another holds 
good for the relation obtaining in the great majority of cases. 
It was recorded in the previous paper on Equisetum that the super¬ 
position of the meshes to the traces above which they arise was sometimes 
disturbed by a change in the number of traces in successive whorls. 
Owing to the much greater variation in the number of members in 
successive whorls of Cone B of E. maximum , and to the irregularity 
of their insertion, this disturbance of what may be regarded as the primitive 
position of the meshes (viz. one vertically above the traces) is much more 
widespread in this cone than in the others. But even in Cone B, in the 
parts in which the axial xylem is well developed and numerous fresh 
meshes arise, and in which there is no great irregularity in the number and 
position of the traces, the superposition of the meshes at their point of origin 
to the traces can usually be clearly seen. In Cone A this superposition 
