Se ee 
- fig. 2 there are shown four plants, two of 
1899] LIFE-HISTORY OF LEMNA MINOR 41 
another four to six generations of plants, 
only one of which is fully formed. In 
=. 
anes 
mee 
which (a and 4) are fully formed, one 
(c) is about half the adult size, and one 
(d) is a very young plant. With high 
magnification it would be possible to dis- 
tinguish the beginning of a yet younger 
plant from d. The plants 6 and c¢ each 
bear flowers (e¢ and frespectively). ig. 
Z is from the ventral side, so that the 
roots (r) of the three older plants are 
shown. : 
The root arises from the lower side of 
eo 
/~ 
a 
cA =e 
AO pa o 
ft 
ahi 
rh) 
Ce 
oan 
oe 
es eg eG ee 
es 
oie 
yan een aa 
[4 
a 
oes 
ae 
“recs 
ae 
ao 
Fic. 3. Young frond sectioned transversely to flat surface, showing young root 
low. a, root cap. 6, meristem region. X 1375. 
Fics. 4, 5. Young roots, each showing temporary epidermal sheath, root cap, and 
the main body of the root. a, meristem cells. X 760. 
