CHAP. II. 
OVULE. 
213 
stalk the axis ; all which, in eases of retrograde metamorphosis, 
are converted into stem and green leaves.” (De Antholysi 
Prodromiis, § 44. 76. t. 5. f. 4, 5.) I should rather say that 
the evidence goes to prove that the ovule is a leaf-bud in a 
particular state, that the integuments are scales (i. e. rudi- 
mentary leaves) rolled up and united at their touching 
margins, and that the nucleus is the growing point, to which 
1 have already on so many different occasions directed at- 
tention. 
In almost all cases the ovule is enclosed within an ovary, 
as would necessarily happen in consequence of the convolute 
nature of the carpellary leaves : but if the convolution is im- 
perfect, as in Reseda, the ovules are partially naked ; and if 
it does not exist at all, as in Cycadaceae and Coniferoe, the 
ovules are then entirely naked, and, instead of being fertilised 
by matter conveyed through the stigma and the style, as in 
other plants, are exposed to the direct influence of the pollen. 
This was first noticed by Brown ; and, although since contra- 
dicted, seems to be perfectly true. 
When the ovules are attached to the placenta by a kind of 
cord, that cord is called the funiculus (Plate V. fig. 26. a), and 
is a prolongation of the placenta. 
In the beginning the ovule is a pulpy excrescence (Plate 
V. fig. 16.), appearing to be perfectly homogeneous, with no 
trace of perforation or of envelopes. But, as it advances in 
growth, it is gradually (Plate V. fig. 17. to 21.) enclosed in 
two sacs or integuments, which are open only at their apex, 
where, in both these sacs, a passage exists, called the foramen 
(Plate V. fig. 21. a) ; or, in the language of Mirbel, exostome 
(fig. 25. a) in the outer integument, and endostome (fig. 25. h) 
in the inner integument. The central part is a fleshy, pointed, 
pulpy mass, called the nucleus (Plate V. fi^. 19, 20. a, 22. K 
23. e, 24. 25.6, 27. c). 
The outermost of the sacs (Plate V. fig. 22. c, 23. «, 25. c) 
is called the primine. It is either merely a cellular coating, 
or it is eventually traversed by veins : these are sometimes 
very apparent, as in the Orange tribe, and Mirbel seems 
disposed to think that they often exist in a rudimentary state^ 
p 3 
