546 
APPENDIX. 
[B. 
valuable and original Analyse du Fruit. The ovulum has, 
according to him, but one covering, which in the ripe seed 
he calls episperm. He considers the centre of the hilum 
as the base, and the chalaza, where it exists, as the natural 
apex of the seed. 
M. Mirbel, in 1815, though admitting the existence of the 
foramen or micropyle of the testa * * * § , describes the ovulum as 
receiving by the hilum both nourishing and fecundating 
vessels t, and as consisting of a uniform parenchyma, in 
which the embryo appears at first a minute point, gradually 
converting more or less of the surrounding tissue into its 
own substance; the coats and albumen of the seed being 
formed of that portion which remains 
In the same year, M. Auguste de Saint Hilaire § shews 
that the micropyle is not always approximated to the um- 
bilicus ; that in some plants it is situated at the opposite ex- 
tremity of the ovulum, and that in all cases it corresponds 
with the radicle of the embryo. This excellent botanist, at 
the same time, adopts M. Turpin’s opinion, that the micro- 
pyle is the cicatrix of a vascular cord, and even gives in- 
stances of its connexion with the parietes of the ovarium ; 
mistaking, as I believe, contact, which in some plants un- 
questionably takes place, and in one family, namely, Plum- 
baginese, in a very remarkable manner, but only after a 
certain period, for original cohesion, or organic connexion, 
which I have not met with in any case. 
In 1815 also appeared the masterly dissertation of Pro- 
fessor Ludolf Christian Treviranus, on the developement of 
* Elcm. de Physiol. Fcg. et de Bot. tom. i. p. 49- 
t tom. i. p. 314. 
t Id. loc. cit. 
§ Mem. du Mus. d'Hist* Nat. ii. p. 270, et seq. 
