CONTRIBUTIONS TO BOTANY. 
JG.3 
sition of sclerogen within or around its cells, and that, by the 
spreading of the raphe under its endodermal surface, the latter 
has become almost isolated from it, in the form of a separable 
opake pellicle. The existence of the micropylar opening, closed 
externally by the cicatrix before described, is a still further con- 
firmation of the origin of the bony tunic of the seed in the 
Styracinece. 
The essential differences observable in the floral structure of 
the two families under consideration now remain to be considei-ed. 
I have already alluded to the facts long since given in Prof. 
Lindley^s ‘Vegetable Kingdom' (p. 593 a): these details, as 
before mentioned, were subsequently combated by Dr. Asa Gray; 
fleshy aril-like coating containing the vessels of the raphe ; and as these 
two integuments are considered to be one, it has been termed “ a baccate 
testa.” On the other hand, I have suggested reasons why these coats 
should be regarded as essentially distinct, both in their nature' and origin. 
I refer the reader to those arguments (Ann. Nat. Hist. 3 ser. i. 280), which 
show the improbability that one half of the tissues of the ])rimine should 
become converted into a thick bony shell, while the other half remains 
soft and fleshy. On the contrary side, this last-mentioned view is defended 
by citing the case of the fruit of the Almond {ibid. 3 ser. i. 35/), where 
the nut is supposed to be formed by the deposition of sclerogen ipjon the 
endoderm of the young carpel, leaving its outer surface unchanged in its 
nature to become the fleshy part of the fruit. But this conclusion appears 
to be founded on an unsound basis, because we have convincing evidence, 
from the position and course of the fila nutritoria (from their origin in the 
torus to the funicle of the seed), and also from the presence of the woody 
fibres in the substance of the nut, resulting from the lignification of the 
nerves of the carpellary leaf, that the nut of the Almond is a solidification 
of the entire carpel, and that its fleshy covering is the growth of an expan- 
sion of the torus, as DeCandolle has shown (Organ. Veg. ii. 40. tab. 43. 
f. 1, 2), citing Nuphar as an examjrle, where a thick fleshy covering, ana- 
logous to the coating over the Almond nut, surrounds the united carpels, 
without any portion of its substance being interposed between them, wliich 
would necessarily occur if that coating had formed any part of the original 
carpellary leaves. Gaertner demonstrates the existence of a similar peri- 
pherical thick envelope around the elastic cocci of the EuphorbiacetE (De 
Fruct. Croton, pi. 10/ ; Jatropha, ])1. 108, 109, &c.) : these cocci contain- 
ing manifest nervures, show us that each is an ossified, distinct, and entire 
carpel ; their adjacent sides, which split from one another, have no indica- 
tion of the intervention of any portion of the peripherical envelope, which 
would infallibly have taken place had that external portion ever belonged 
to the normal carpels. DeCandolle also alludes to the instance of Peeonia 
Moutan (loc. cit. p. 40, et Syst. i. 388), where the ovary, from the expan- 
sion of the torus or disk, becomes covered by a fleshy membranaceous 
urceole which completely surrounds it, and through the perforated ajjex 
of which the stigma is exserted ; this is at first quite free, but it afterwards 
appears to form part of the fruit. To this source we may attribute the 
origin of the fleshy covering of many fruits, analogous to the instance of 
Nuphar; and we must consider the nut of the Almond as the growth of 
the entire carpel, and its fleshy covering as an emanation from the torus, 
confluent with it. 
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