214 LEMNACES. 
apex of the nucleus, is radicle, and the small body at its base 
the gemmule, the cotyledon encloses the radicle by means of 
two processes, 80 far all is clear. Not so however when he ex- 
plains Richard’s drawing. He says the first part that issues 
is radicle, consequently he makes the bifid end of the coty- 
ledon the radicle. Не then points out that tbe body which 
issues from between these is the gemmule ! 
He is not decided as to what becomes of the radicle, 
for he says the radicle, or a secondary one, elongates itself on 
the sides of the opercule, can the young frondule be the part 
which is elongated into a radicle. I think not, or if it is, the 
sheath is derived from the cotyledon lip of Wilson, which he 
says is not the case, If we look at those orders which con- 
tain frondose plants we shall find that the number is, one to 
each kingdom. 
Podostemez among Dicotyledons, Lemnacez, among Mo- 
nocotyledons, with the exception of this, the two orders 
have but little in common. It is somewhat remarkable that 
the passage of Dicotyledons into Acotyledons, through the ve- 
getative organs of Podostemon, is much more perfect than 
that of Monocot’s through Lemna. 
It is more especially to the lower forms of Hepatice that 
Podostemon has its relation, it will be necessary to ascertain 
whether the flower literally breaks out, as well as the young 
rond. 
M. Adr. Jussieu states that the embryo of Lemna is com- 
posed of an ovoid radicula and gemmule, united along their 
axes by a farinaceous body, which, se dilatant autour d'elles 
dans tous les sens, se prolonge en bas jusqu'au niveau infé- 
rieur de la radicule, ex haut beaucoup au-dessus dela gem 
mule qu'il ne laisse en communication avec l'exterieur que 
par un vide ou canal central. 
This farinaceous mass, which forms almost the entire mass 
of the embryo, ought naturally to be called the cotyledon, 
since the analogous body in a Zosteracea is so called. 
M. Jussieu considers the fronds as the branches of an ap- 
