AND ON POLYEMBRYONY IN THE HIGHER PLANTS. ll 
is scarcely half as broad as the funiculus which is formed sub- 
sequently. As, moreover, in Draba verna there is no em- 
bryo-sac, it is evident that the funiculus must appear like a 
direct continuation of the pollen-tube, since, as in many of the 
preceding cases, it persists long after impregnation. 
Less clearly than in the cases hitherto mentioned, and ap- 
parently speaking strongly in favour of M. Schleiden’s new 
theory, do the impregnation and the formation of the embryo 
take place in the Liliacee and similar families. In these plants 
there is also no embryo-sac; the pollen-tube penetrates the 
apertures of the two tunics, and passes through the loose cel- 
lular mass of the summit of the nucleus down into the cavity 
which has been formed in the interior of the nucleus, and oc- 
cupies the place of the embryo-sac in other plants. Itis the apex 
of the pollen-tube which has penetrated into the upper end of 
the cavity of the nucleus which here swells in a greater or less 
degree to a clavate or globular form, at times attains a very 
considerable size, then divides itself by septa into several large 
cells, constricts itself from the still adhering pollen-tube, and 
is finally transformed by the formation of new cells in its 
interior into the embryo. Here likewise there are traces of a 
funiculus, which, however, does not separate so decidedly from 
the actual embryo as has been seen in the previous cases. On 
plate xv. of my Physiology of Plants there is in figs. 1—8 a 
series of drawings of the phenomena of impregnation here 
mentioned, and more particularly of the Crown imperial, &c. 
In this case also it is not the apex of the pollen-tube, out 
of which the embryo is formed ; but.this apex serves merely as 
the substratum to the formation which represents the young 
embryo, and which results in the first instance from the secret 
action between the contents of the pollen-tube and the contents 
of the cavity of the nucleus. The apex of the pollen-tube will 
certainly not be transformed to an embryo outside of the cavity 
destined for the formation of the embryo; and the case of an 
extra-nucleal pregnancy, which is said to have been met with 
m the genus Orchis, appears to me to be founded on an 
error. In thus regarding it I am the more justified, as I have 
found that M. Schleiden, the author of that communication, 
has not quite correctly conceived the formation of the embryo 
in the above genus ; the drawings which he has given in illus- 
tration are all of a much later period, and he was thus some- 
