239 
Cone and Fertile Stem of Equisetum . 
distributed so close to one another round the axis that the tendency to 
concrescence of sporangiophores, observable in most species of Equisetum , 
is well marked. Often, of course, the concrescence is only partial. I have 
observed as many as three sporangiophores to be concrescent in their basal 
portions. 
The sporangiophores of E. hyemale are less massive and shorter. The 
transverse sections of my specimens of the cone of this species recall the 
cones of E. limosum. But in E. hyemale the sporangiophores and their 
traces ; are larger relatively to the axis and the cortex wider than in 
E. limosum. No definite central cavity had made its appearance in my 
cones of E. hyemale , though the central tissues were slightly torn. In 
specimens of E. limosum of the same age and size the development of the 
central cavity is more advanced. 
In E. giganteum the traces of the sporangiophores depart either from 
the "middle or from at or near the edge of an axial strand or band of 
vascular tissue ; traces arising in the former position may be termed 
8 9, 10 11, 13 12, 14 15, Ifi . 17 
Text-fig. i. Divergence of the sporangiophore-traces of the lowest whorl of Cone A of 
E. hyemale. x I3|. a. v. b. - axial vascular bundle ; c. = cortex ; e — epidermis; and sp. — spor- 
angiophore 
median, those in the latter position lateral or slightly internal. Or again, if 
a bundle remains very narrow when giving off a trace, the latter may be 
attached to the whole width of the axial strand (cf. Browne (1), pp. 671-2). 
In E. hyemale most of the traces are median or slightly internal, hardly any 
are truly lateral. In this species, too, the trace may be practically as wide 
as the strand from which it arises. This is generally so when the strand 
dies out after giving off a trace. 
Though none of my cones of E. hyemale were old the sporangiophores 
and traces of the lowest whorls showed a tendency to be directed obliquely 
downwards. This phenomenon was most marked in Cone A. Text-fig. 1 
reproduces the conditions obtaining in the lowest whorl of this cone. The 
actual downward deviation is less than in E. maximum, for the cone is on 
a smaller scale ; but, as seen in the text-figure, the angle may be rather 
acute. In this whorl no trace was deflected for more than 294 ix, and the 
average distance for all the traces of the whorl was but 124 fx. In the whorl 
R 
