IN FLOWRRING PLANTS. 159 
really quartine, i. e. the embryonary sac. The figure given is 
probably incorrect, as I have never seen such an instance of 
absolute union. 
Mirbel describes its growth as in general simultaneous, and 
commencing from every point of the sides of the ovulum ; in 
some instances, as in some Leguminous plants, it commences 
from the apex of the cavity, and grows downwards. The 
earlier periods of its growth have escaped this well known 
and eminent physiologist. 
My own observations lead me to conclude, that from what- 
ever point it is developed, it first lines the cavity of the nu- 
: cleus, subsequently becoming filled with more or less cellu- 
lar tissue. And in albuminary forms the primary formation 
of cells commences at the end at which the embryo is situated. 
It is even confined to this end for sometime, so that we may 
have an embryonary sac fleshy at one end, and membranous 
at the other. 
M. Mirbel says of the quartine, that it has escaped notice 
owing to its having been confounded with the tercine, and 
that he has only seen it in those ovula, the tercines of which, 
become united in a very early stage to the secundine. Me- 
moire 1, p. 9. 
Embryo. 
This organ first appears in the form of a cellular vesicle, 
attached by a slight cellular pedicel to the apex of the 
embryonary sac. Its development consists in the appearance 
of other additional cellules in its interior, which cellules 
always contain much active molecular matter. It continues 
for sometime globular. 
In Dicotyledones, the notch indicating the division of the 
cotyledons soon appears, and at or about the same moment 
the radicular end assumes a somewhat oeniesk form. 
The subsequent 
pitulation, indeed they consist asiels rof an increase of growth. 
e plumula is the last part formed. 
The radicle always corresponds to the apex of the embryo- 
nary sac, and in almost all cases to the apex of the nucleus. 

