448 MR. W. C. WORSDELL ON THE 
striking approach to the more primitive conformation and 
structure of Ferns, I began my study of the seedling plant with 
the full expectancy of discovering some primitive character or 
other which would serve to distinguish it in some way from 
Cycads generally. And in this I was not disappointed, for the 
especial point to be insisted upon in the following description is 
the presence of concentric bundles in the cotyledon, which must be 
regarded as of great importance ; beyond this, the only character 
worth noting is the presence of obliquely outgoing strands in the 
hypocotyl,which supply an endogenously arising lateral appendage. 
The young plant was attached to the megasporangium by its 
cotyledons (Pl. 20. fig. 10); it bore a small foliage-leaf of four 
pinne and a very short radicle (figs. 11 & 12). 
Each cotyledon has, in the upper part, four bundles arranged 
in a row parallel to the greatest width ; each bundle consists of 
well-developed phloem, a small protoxylem-group, and several 
centripetal tracheides (fig. 13). In the lower part of the lamina 
of the cotyledon and in its stalk, besides the row of four or five 
bundles, there are two or three others towards the ventral side, 
which may be orientated like those of the normal row or may lie 
sideways. Ascending towards the upper part of the organ, 
however,the phloem of these inner bundles tends to disappear, and 
about halfway up it may be either quite absent or represented 
by but a few inconspicuous elements. (This may also occur m 
the basal part.) At length, in the upper region, these bundles 
entirely lose their phloem and their xylem becomes united each 
with one of the normal bundles. 
Descending towards the basal region, the bundles gradually 
e majority are com- 
become more and more concentric, until th " 
rie, 
pletely so. Those at the ends of the row remain semi-concen 
being still more or less collateral. The concentric bundles are 
extremely small, offering a striking contrast in this respect to the 
much larger collateral bundles of the upper laminar region. Their 
centre is occupied by a small group of primary xylem; no secon- 
dary tracheides are present. Primary phloem, at least in some 
bundles, would appear to occur all round (fig. 15); in other 
cases the bundle is enclosed on the ventral side by second y 
phloem only. It will thus be seen that in the cotyledon of this 
plant a clear case exists of primary concentric bundles. I know, 
moreover, of no other instance in the vegetative foliar organs o 
modern Cycads where such structures are met with. 
