Anatomy of the Cone and Fertile Stem of Eqtiisetum. 257 
points of departure of these traces we find well-developed reticulate 
tracheides, and it is, as pointed out by Jeffrey (Jeffrey, 2 ), only higher up, 
when the nodal tracheides die out, that the parenchymatous meshes make 
their appearance. 
A node of the sterile stem was cut serially for purposes of comparison, 
and afforded an example of increase of bundles in successive internodes. In 
the internode there were twenty-five bundles, showing slight variation in 
size and irregularity in distribution, but clearly equivalent to one another. 
Twenty-five traces were given off. In the upper internode there were 
twenty-six bundles, two of them being very close together. This couple 
of bundles, of which one was much smaller than the other, results from the 
forking of a strand at its very origin, i. e. at the node. In other words, we 
get at this level the formation of a parenchymatous mesh independent 
of the departure of a trace. Such fission seems to be the usual mode of 
increase of the bundle in successive internodes. Similar cases leading 
to increase in the number of bundles were met with in the fertile stems and 
axes of cones, not only in this species, but in E. arvense (Browne, p. 679). 
The disturbance of the alternation of the bundles of successive internodes is 
narrowly restricted to the strands involved in the forking. But except for 
such irregularities, due to the increase or decrease of the number of bundles 
in successive internodes, the parenchymatous meshes of the stems of 
Equisetum maximum, fertile and sterile alike, seem to be disposed very 
regularly above the traces, so that the bundles and therefore the carinal 
canals alternate very regularly from one internode to the next. I am con¬ 
sequently unable to understand Sykes’s longitudinal reconstruction of a node 
of E. maximum (Sykes, p. 130). Here two carinal canals belonging to 
successive internodes are drawn as superposed. The structure of the nodal 
tracheides of this specimen was exceptional, and exceptional superposition 
of the bundles at the node may have occurred also ; but as no mention of 
so remarkable a course of the bundles is made, it is possible that the super¬ 
position of the canals in the diagram is due to a slip of the draughtsman’s 
pencil. Jeffrey, however, figures a case of non-alternation of the bundles at 
the nodes of E. hiemale, and states that in this species such a phenomenon 
is not rare (Jeffrey, 1 , p. 175). To return to the small bundle, the latter is 
at first very close to its sister bundle, and has no carinal group of tracheides. 
The two lateral groups of metaxylem characteristic of the Equisetaceous 
bundle are, however, developed. These have been torn in part, and are 
very poorly lignified; sometimes, indeed, the lignification appears to be 
absent for a section or two. But this tearing and poor lignification of the 
xylem in the internodes is quite common in stems of Equisetum . As 
we pass up the internode a small carinal canal appears, but no clearly 
lignified elements were developed below its origin. Those which presum¬ 
ably occurred in the region now occupied by the carinal canal have, of 
