343 
of Lepidostrobus Brownii , Schpr . 
usually found in the calcified nodules. The. facts acquired 
may assist in the interpretation of the less perfect lime- 
incrusted fossils, and will be of value for comparison with 
(i) other Lepidostrobi , (2) vegetative stems of Lcpidodendron , 
and (3) living Lycopodinous plants. When the comparison 
is made with a fine transverse section of a Lepidostrobus from 
a lime-nodule, supplied to me by Mr. Lomax, the plan of 
structure of the axis is found to be virtually the same ; 
the chief difference lies in the existence of vacant spaces, 
where the softer tissues of the phloem and the trabecular 
cortex occur in Brown’s cone. It seems probable that in this, 
as also in other cases of such cones, observed or figured by 
other writers, the complete structure was essentially similar to 
that above described. A point for remark is, however, the 
wholesale disappearance of the more delicate tissue ; but 
if the limits of those tissues, which have been preserved 
in specimens from the lime-nodules, be carefully examined, 
it will be found that many of the cell- walls end abruptly, just 
as would be the case if, in such tissues as those shown in 
our Fig. 4, the darker lignified walls were preserved, while 
the more delicate, probably cellulose, walls were entirely 
broken down. 
The structure of the vegetative stems of various types 
of Lepidodendron is well known, so there will be no need to 
enter on a comparison of the vascular tissues ; our object will 
rather be to consider the nature of their cortex, and to 
compare it with that of Brown’s cone. It will presently be 
shown that there is considerable variety in the mode of 
development of the cortex in the species of living Lycopods. 
The same appears to have been the case with the fossils. 
Three distinct bands of the primary cortex seem to be 
commonly present in the vegetative stem of Lepidodendron , 
exclusive of the tissues resulting from secondary change : 
they do not correspond to the three cylinders described 
by Solms 1 , and illustrated by his Fig. 23, for these include 
Fossil Botany, p. 220. 
