VES e SOINS IRE ea eee i E CONES T ii au 
A EUROPEAN PETRIFACTION WITH FOLIAGE. 487 
(3) Within this is a circle a dozen or so cells thick, much more cork-like 
than like wood. (4) The central space within this consists of irregular pith- 
like tissue among which groups of thick-walled cells are visible, and of 
which the central portions are largely disorganised. 
The nature of this curious circle of tissue is a point of interest. Tts 
central position and large size make it evident that it is not a chance “ pith- 
bundle ” such as oceur in some cycads. It might conceivably be the dying 
out of the cylinder of a large primary root, and it is most unfortunate that 
there was not material for just one section below r to make clear whether 
the tissues were carried down into a definite vascular cylinder or not. The 
way it dies out above makes it clear that were ita vascular cylinder it had 
no connection with that of the stem. Such primary roots are, I believe, not 
known in the cyeadean cohorts. 
A suggestion which has more to recommend it is that this i« the upper 
part of a separation layer which, at some time, had separated this small stem 
from another, a parent stem, from which it may have sprouted. The erratic 
sprouting of seedling-like buds and their development into separate stems or 
lateral branches in the living Cycas circinalis (see Stopes, 1910) seems to 
offer what may be a close comparison. Were this view accepted we must 
look on the young stem of this new fossil as a sprowtling and not a seedling. 
While it is only wise to reserve judgment about this, it may be mentioned 
that, from my experience with living cycad tissues, I incline to favour the 
latter interpretation. Also Dr. D. H. Scott, F.R.S., who very kindly 
examined slide r, added an argument in favour of this view, saying in a 
letter to me, “ I entirely agree with your interpretation, 7. e. that the ring of 
secondary tissue round the centre is a separation layer and not vascular. I 
judge not only from the look of the cells, but from the fact that the tissue 
inside the ring is disorganized, just as would be the case if it were a separa- 
tion-layer. I imagine the layer was dome-shaped and that this section cuts 
through the sides of the dome.” 
The leaf-traces come off from the vascular axis as single, solid ares, with 
considerable quantities of tissue forming a fan ; this spreads out and breaks 
up into a circle of bundles as each passes directly out through the cortex 
into the leaf-bases in the usual way. 
The cortex consists of a mass of large-celled soft tissue, in which run 
numerous * gum-canals " larger in diameter than the tissue-cells amid which 
they lie. 
As will be apparent from figs. 1 & 2, Pl. 19. the leaf-bases, though rela- 
tively small compared with the type species, B. Gibsonianus, are yet large 
proportionately to the size of the stem itself. The leaf-bases measure about 
1x8 em. and are thus actually very little less than those of the full-sized 
trunk of B. Allehini (Stopes, 1915). They are of the typical rhomboidal 
shape and spiral arrangement, The ground-tissue and vascular bundles 
