450 Solms-Laubach'—On the Fructification 
Hitherto indeed stems of Bennettiteae have been placed with- 
out hesitation among Cycadeae, and it is possible that many 
of the mesozoic Cycad leaves grew on Bennettitean stems. 
But still it must not be forgotten that we have at present no 
proof of the correctness of this view. There are resemblances 
between the two groups which cannot be disputed ; but 
there are such important differences, especially in the structure 
of the flower, to be set against these, that we are driven to 
seek for other groups to fill up the chasm. 
If we suppose that, as a matter of fact, a real relationship exists 
between Bennettiteae and Cycadeae, it can still be shown most 
distinctly that the one group cannot be derived from the other, 
but that the two must be the terminations of different phyla 
springing from the same stock. For the Cycadeae, which we 
should naturally consider to be the younger group, are far behind 
the Bennettiteae in the complexity of the structure of the flower, 
while the Bennettiteae on the other hand show a much simpler 
and primitive structure in the vegetative organs. That the 
peculiar two-stranded girdle-forming leaf-tracesof Cycadeae are 
a comparatively new character which has made its appearance 
in their progress towards perfection, is proved in my opinion by 
the fact that in the flowering extremities of the shoots of the 
sympodium, where the vegetative development is less vigorous, 
we may observe in the course of the vascular bundles, which 
resembles that of Bennettiteae, a return to the primitive more 
simple arrangement \ This circumstance seems to me to be 
the most important argument for the approximation of the two 
groups. We do not know what was the appearance of the 
parent-group from which the two divergent phyla proceeded : 
but it must in all probability be sought in very remote epochs 
of the development of the earth, for we have some certain 
knowledge of the type of the flower in the genus Cycas from 
the base of the Lias ; and therefore I have no doubt that this 
parent-group may have given rise to various other derivative 
types besides those of Cycadeae and Bennettiteae. The idea 
which we frame for ourselves of the original parent-stock will 
1 See my fuller account of this in Bot. Ztg., 1890, p. 177, 
