160 DEVELOPMENT OF THE OVULUM 
The green colour of the embryonary sac in its early stages 
did not escape M. Brongniart. 
The communication between the embryo and the embryo- 
nary sac is always cellular ; never indicating the slightest 
appearance of vascularity. And yet many embryos are vas- 
cular. 
The duration of the funicle or cord of communication is 
various, generally no trace can be discovered of it at the pe- 
riod of maturity of the embryo. 
In others again as in Cycas and Gnetum it is persistent, 
and often of very great length, in such the radicle is said to 
have an organic connection with the seed. M. Brongniart 
states that the embryo sometimes becomes isolated from its 
attachment at an early period, this is probably due to mani- 
pulation. 
In the only two instances I know of in which no nucleus 
exists, the radicle corresponds to that part of the embryonary 
sac nearest to the base of the style, and this is in both these 
cases the base of the sac itself. Hence it may be stated, that 
the radicle always corresponds to the upper part of this sac, 
viewed relatively to the configuration of the seed. 
I have never seen an instance of such an embryo as M. 
Brongniart mentions in three instances, viz. the central cell 
being the largest, it leads him to ask if it may not be the 
spermatic granule ! 
Of the direction of the cotyledons with regard to the faces 
of the seed I can state nothing positive, they are often alter- 
nate, and as often opposite to the true faces of this body, and 
I am acquainted at least with one instance in which, though 
originally opposite, they have become alternate to these faces 
uring their development. 
The modifications undergone by the cotyledons during 
their development require examination. I allude to their 
occasional crumpled state, etc. 
All cases of single cotyledons among exogenous plants 
are due to their mutual cohesion, which in no instance per- 
haps extends equally throughout their extent. A slit will be 
visible near the collet, and on either side of the embryo as in 
