2 1 2 Worsdell . — The Vascular Structure cf 
xylem of the bundle is greatly reduced in quantity, its 
elements less sharply defined, and less brightly stained. The 
centripetal xylem usually exceeds it in quantity. 
Female Sporophyll. This organ is situated on the main 
axis of the vegetative stem, and not on a strobilus as in all the 
other genera. It occurs in whorls alternating with the foliage- 
leaves. It is larger in size than the sporophyll of any other 
genus, and more nearly resembles a foliage-leaf in external 
conformation ; herein lies probably a more primitive and less 
modified character ; the sporophylls of other genera, from 
their crowded arrangement on a cone, having undergone 
a much greater modification in form. These sporophylls 
differ also from all others in possessing a very long stalk, and 
in bearing a larger number of megasporangia than two, these 
being situated, not on the terminal expanded portion of the 
sporophyll, as in other genera, but at regular intervals on 
short projections from the stalk. The size of the sporangia is 
in correspondence with that of the sporophyll, being the 
largest of the whole order. 
The structure of the vascular bundles of the sporophylls is 
remarkable and interesting ; it is precisely that which is 
found in the bundles of the peduncle of Stangeria. The 
strands, as seen in transverse section, are arranged laterally in 
groups which form a single row (Fig. i). Some bundles or 
groups of bundles are entirely or partially surrounded by 
a thick zone of cells, probably pericyclic, filled with dense 
protoplasmic contents and conspicuous nuclei. This, again, is 
surrounded by a belt of stone-cells, possibly representing an 
endodermis, which have conspicuous reticulate thickenings on 
all their walls. But these two tissues are of inconstant 
appearance. 
The centrifugal xylem and the phloem are of very great 
development, which is quite equal to that of the bundles in 
the peduncle of other genera, and is in evident correlation 
with the size and number of the sporangia which they have 
to supply. The centripetal xylem, either in contact with 
the protoxylem, or as scattered tracheides or groups of 
