IN FLOWERING PLANTS. 161 
Loranthus. Even the cotyledon is not absolutely essential, 
as is proved by Stylocoryne. 
With respect to the correspondence of the different parts 
of the embryo with the envelopes of the seed, it is almost 
needless to observe that the radicle almost invariably points 
to the situation of the foramen. The cotyledons correspond 
to the chalaza. 
M. Brongniart p. 116, has endeavoured to work out more 
correspondences, and arguing on unequal development as 
indicated by a certain amount of laterality between the cha- 
laza and apex of the nucleus ; he is of opinion, that he can 
determine the position of the embryo, by the relative posi- 
tions of the chalaza and apex of the nucleus (mamelon 
d'impregnation. He gives an exception in Commelinez, 
but explains it away on the grounds of the minuteness of the 
embryo, as compared with the bulk of the nucleus. 
On similar grounds his second position, that the curved or 
rectilinear figure of the embryo may be inferred from the 
figure of the nucleus, becomes invalidated. For it is at once: 
obvious, that taking even the maximum amount of curvature 
known, it will never influence the form of a minute em- 
bryo. And I believe, I can cite a case in point in Stauntonia, 
The explanation upon which M. Brongniart's 3rd posi- 
tion is founded,* although perhaps applicable to the cases he 
has’ cited, is not so, to certain Polygonez in which the em- 
bryo is lateral, although the correspondence between the 
chalaza and apex of the seed, is as directly opposite as could 
be wished. j 
Several points connected with the growth of the embryo. 
require investigation, viz. crumping of cotyledons, the em- 
bryo of Barringtonia, and of Myrtacez, Guttifera, etc. in 
which it is a homogeneous mass. 
* [Cotyledons aborigine distinct ; subsequently unite, often always a double 
it. 
sli 
* Y 
