LEMNA. 219 
plantule, e its attachment, sheath basilar of radicle, g 
new gemmule. 
. 12a. Seed plumule and young frond detached, a body of 
seed, 5 radicle, c fissure, the apex of the nucleus fallen 
off by accident. 
12c. Plumule detached, a its attachment, 5 fissure. 
124. Young gemmule, and axis with radicle, which is 
evascular, a axis which terminates in the attachment, 
b novell. gemmule. 
There is a tendency to refer to the typical form in the ob- 
lique exit of the plumula, although this must still be consi- 
dered as escaping almost from the centre of the radicle. 
As also, in the non development of radicle from the plu- 
mula, which after having performed its functions, dies like 
other primordial leaves, separating about the period when the 
second frond is well developed, both it and the radicle, as their 
periods of service draw to a close, become white, the radicle 
a good deal sooner than the other. 
There is some analogy in appearance between the plumule 
and an ovulum, see figs. 0,0, for the gemmule which may be 
supposed to represent the nucleus, is at first exserted, sub- 
sequently becoming enclosed, to be again exserted, in which 
latter point it differs. 
Lemna continued CCLXII. Fig. II. 
1. Germinating plant, @ upper lip of radicle, à seed 
towards chalaza, c plumule, d first frond, e second do- 
2. Do., more advanced, the seed aud embryo separate rea- 
dily. The apex of nucleus still adhering to the lower lip 
of the fissure, both the radicle and plumule are whitish, 
а upper lip of radicle, 6 near apex of seed, с plumula, 
d first gemmule, d a its attachment, e 2nd gemmule 
J fissure of its exit. 
3. Young radicle, æ cellular sheath eontinuous with cuti- 
cular tissue; 6 radiele, its sheath scarcely distinct, or 
rather it is the sheath, the radicle itself is not yet deve- 
loped. 
