334 Bower —On the Structure of the Axis 
figures of it, which do it very scant justice 1 ; and as regards 
the central axis he merely remarks that, 'The axial strand, 
which is surrounded by numerous transverse sections of leaf- 
traces, has the structure of Lepidodendron HcircourtiV 2 . On 
a previous page Solms has pointed out (p. 226) that this name 
covers two distinct species, and of these Brown’s cone seems 
to resemble the form styled by him L. Williamsoni , as regards 
the structure of the axis. The distinctive points are (1) the 
absence of secondary thickening; (2) the central parenchy- 
matous pith ; (3) the sinuous outer limit of the xylem, the 
point of insertion of the leaf-trace bundles appearing in the 
transverse sections as sharp, outward-pointing teeth ; (4) the 
absence of bast-fibres from the bundles of the leaf-trace. All 
these characters, which are illustrated in the drawings of 
L. Brownii to be described below, correspond to those given 
by Solms for Lepidodendron Williamsoni. 
Turning now to the details which may be observed in the 
sections preserved in the British Museum, it must first be 
stated that I confine the present observations to the structure 
of the axis ; a detailed description of the sporangia is being 
prepared for publication elsewhere. 
Fig. 1 is a copy of a photograph which represents the axis 
cut transversely, together with the bases of thirteen sporo- 
phylls. At the centre is the bulky parenchymatous pith, 
which merges, without any sharp limit, into the narrow dark- 
looking ring of xylem ; this has a crenulated margin, and 
gives off from the projecting points bundles of the leaf- trace, 
which at first traverse a dense inner band of ground-tissue. 
As they reach the margin of this band, the tissue directly sur- 
rounding them becomes more lax and filamentous, till they 
finally emerge into the wide clear space intervening between 
the central mass of tissue and the dark peripheral band of the 
cortex. In this space the leaf-trace bundles appear as isolated 
dots ; but in their oblique course they ultimately reach the 
peripheral band of cortex, traverse it, and finally pass out- 
1 Solms, loc. cit. Figs. 25 A, B, p. 233. 
2 Fossil Botany, p. 238. 
