418 Mr. Robert Brown on the Structure of the 
To the earliest of the opinions here quoted, that which con- 
siders the female flower of Coniferae and Cycadez as a naked. 
pistillum, there are two principal objections. The first of these 
arises from the perforation of the pistillum, and the exposure 
of that point of the ovulum where the embryo is formed to the 
direct action of the pollen; the second, from the too great 
simplicity of structure of the supposed ovulum, which, I have 
shown, accords better with that of the nucleus as existing in 
ordinary cases. 
To the opinions of MM. Richard and Mirbel, the first ob- 
jection does not apply; but the second requires such additional 
weight, as to render those opinions much less probable, it 
seems to me, than that which I have endeavoured to support. 
In supposing the correctness of this opinion to be admitted, 
a question connected with it, and of some importance, would 
still remain, namely, whether in Cycadez and Coniferz the 
ovula are produced on an ovarium of reduced functions and 
altered appearance, or on a rachis or receptacle. In other 
words, in employing the language of an hypothesis, which, 
with some alterations, I have elsewhere attempted to explain 
and defend, respecting the formation of the sexual organs in 
Phzenogamous plants *, whether the ovula in these two fami- 
lies originate in a modified leaf, or proceed directly from the 
stem. 
Were I to adopt the former supposition, or that best agree- 
ing with the hypothesis in question, I should certainly apply 
it, in the first place, to Cycas, in which the female spadix 
bears so striking a resemblance to a partially altered frond or 
leaf, producing marginal ovula in one part, and in another 
being divided into segments, in some cases nearly resembling 
those of the ordinary frond. 
But the analogy of the female spadix of Cycas to that of 
Zamia is sufficiently obvious; and from the spadix of Zamia 
to the fruit-bearing squama of Coniferz, strictly so called, 
namely, of Agathis or Dammara, Cunninghamia, Pinus, and’ 
even Araucaria, the transition is not difficult. This view is 
applicable, though less manifestly, also to Cupressinze ; and 
might even be extended to Podocarpus and Dacrydium. But 
the structure of these two genera admits likewise of another 
explanation, to which I have already adverted. 
If, however, the ovula in Cycadew and Conifere be really 
produced on the surface of an ovarium, it might, perhaps, 
though not necessarily, be expected that the male flowers 
should differ from those of all other pheenogamous plants, and 
in this difference exhibit some analogy to the structure of the 
* Linn, Soc. Transact. vol. xiii. p. 211. 
female 
