GENERAL REMARKS. 213 
Brongniart’s account of Lemna appears to me correct, 
but of what nature the canal is, is another affair. The seed 
certainly has much more the appearance of a dicotyledonous, 
than monocotyledonous plant. Pressureat least makes it a 
perfect dicotyledonous one. Nor must we forget the Opposi- 
tion of the plumula to the radicle, which appears to me 
unusually monocotyledonous. 
Not the least curious point is the attachment of the seed 
by a process obviously of its own substance. 
If it be dicotyledonous, the division of the cotyledons ap- 
pear later in it than any other plant I know. And in this 
it will again approach Monocotyledons. 
The end of embryonary sac next to the apex of the nucleus 
is minutely apiculate. 
here is no trace whatever of the canal when the embryo 
is half developed; ata period when the radicle is of considera- 
ble size, and completely enclosed by the auricles of the coty- 
ledon, it is continuous with the plumule, which is very minute. 
Mr. Brongniart does not allude to, nor does he represent the 
peculiarity of the mammelliform apex of the nucleus neither 
does he mention the precise origin of the scutella or oper- 
calum. According to the section given by him, the seed is 
really docotyledonous. 
I have not been able to determine the canal communicat- 
ing with the plumule, nor have I found that the plumule or 
Brongniart’s radicle, is so far disconnected with them as he 
represents. 
The development of the ovule is a fatal objection to con- 
siderig the plumule as the radicle. Nor must its absolute 
distinctness from the inclosing mass be overlooked. This 
plumule undergoes the same evolution within the embryo, 
as the young innovations do within the fronds. If my idea 
is right, it follows that in all, the Ist frondule will be termi- 
nal, although this would not seem to be the case from Ri- 
chard’s drawing Æ. Brongniart’s explanation is, that the 
body enclosed within the thick end of the embryo, next the 
