ee 
Te ee ee oe ee a eT ee ee ee ee 
1899 } LIFE-HISTORY OF LEMNA MINOR 61 
and Lilaa (18). But, as in Lilian Philadelphicum (15), the suspen- 
sor cells have divided by longitudinal walls and no definite embryo 
cell or cells can be distinguished. It is quite evident that there 
is more of a suspensor than is shown 
for this species in Hegelmaier’s Mono- 
graph in his figs. 3, 4, 5. Other fig- 
ures by Hegelmaier represent young 
embryos of this species as each having 
avery large terminal cotyledon, with 
the small plumule arising laterally near 
the suspensor region. 
After fertilization the cells at the 
tips of the integuments enlarge and 
divide (fig. 59), crowding close 
Fic. 57. Embryo, nucellus, and the peculiarly thickened tips of the integuments. 
760, 
___ Fic. 58. Young embryo attached to the nucellus; the base of the same embryo 
is shown in fig, 59» K 1375. 
Fic. 59. Tips of integuments, the cells of which are enlarged ; the nucellus and 
lower end of the embryo. X 760, 
together until there is a compact tissue of heavy-walled cells 
completely closing the micropyle (fig. 57), forming the so-called 
beak or operculum of germinating seeds. In no case where fer- 
tilization was not accomplished was such a structure seen. 
