556 
APPENDIX. 
[B. 
proof of its correctness must chiefly rest on a resemblance, 
in every essential point, being established, between the inner 
body in the supposed female flower in these tribes, and the 
nucleus of the ovulum in ordinary structures; not only in 
the early stage, but also in the whole series of changes 
consequent to fecundation. Now as far as I have yet ex- 
amined, there is nearly a complete agreement in all these 
respects. I am not entirely satisfied, however, with the 
observations I have hitherto been able to make on a subject 
naturally difficult, and to which I have not till lately at- 
tended with my present view. 
The facts most likely to be produced as arguments against 
this view of the structure of Coniferee, are the unequal and 
apparently secreting surface of the apex of the supposed 
nucleus in most cases ; its occasional projection beyond 
the orifice of the outer coat ; its cohesion with that coat 
by a considerable portion of its surface, and the not unfre- 
quent division of the orifice of the coat. Yet most of these 
peculiarities of structure might perhaps be adduced in sup- 
port of the opinion advanced, being apparent adaptations to 
the supposed economy. 
There is one fact that will hardly be brought forward as 
an objection, and which yet seems to me to present a diffi- 
culty, to this opinion ; namely, the greater simplicity in Cyca- 
deae, and in the principal part of Coniferae, of the supposed 
ovulum which consists of a nucleus and one coat only, com- 
pared with the organ as generally existing when enclosed in 
an ovarium. The want of uniformity in this respect may 
even be stated as another difficulty, for in some genera of 
Coniferae the ovulum appears to be complete. 
In Ephedra, indeed, where the nucleus is provided with 
two envelopes, the outer may, perhaps, be supposed rather 
analogous to the calyx, or involucrum of the male flower. 
