1918] OTTLEY—IMPATIENS 317 
Fic. 40.—Fertilized egg; 1000. 
ne 41-43.—Stages in fusion of the 2 polar nuclei; 1620. 
Fics. 44, 45.—Stages in fusion of second sperm nucleus with endosperm 
aa fig. 44, X1620; fig. 45, X 1625. 
1G. 46.—Vertical section of apex of embryo sac showing 3 endosperm 
nuclei on their way to form micropylar haustorium; another section shows 
endosperm nucleus below original position of primary endosperm nucleus; 
500. 
Fic. 47.—Vertical section- of micropylar portion of embryo sac after 
primary endosperm nucleus has divided several times; sac has enlarged beneath 
filiform si gaiee X 1000. 
Fic. 48.—Portion of endosperm present at one side of embryo sac after 
embryo he formed; X 500. 
IG. 49a, ioe vertical section through micropyle with micropylar haus- 
torium, ca through embryo sac at base of micropyle; young embryo with 
short suSpensor surrounded by endosperm cells; 500; b, vertical section of 
micropylar haustorium as it extends across space from micropyle to funiculus; 
a and 6 are sketches of same haustorium, but taken from different sections; 
X 500 
FIG. 50. Ssieegi through chalazal portion of ovule; chalazal haustorium 
and endosperm cells are filled in while only outline of chalazal tissue is given; 
sketch is from same ovule as fig. 49a, and is a combination of 2 sections; 
X 500. : 
Fic. 51.—Vertical section of chalazal haustorium with surrounding endo- 
sperm cells; haustorium cut somewhat diagonally; X 500. 
Fic. 52.—Vertical section through embryo sac after a many-celled embryo 
has developed; endosperm at base and at one side consists of but one layer of 
cells, at the other side consists of several layers, and in another section of this 
same embryo sac chalazal haustorium occurs in this thickened portion of 
endosperm; 16 
Fic. 53 aa. sketch of vertical section of ovule containing embryo of 
2 cbt yledions: embryo does not show in section; combination of 2 sections; 
Fic. 54.—Outline sketch of vertical section of embryo sac at time of fertili- 
zation or slightly later; growth has taken place at antipodal and at median 
regions; 162 
Fic. 5§.—Outline sketch of vertical section of embryo sac after embryo 
has been developed; narrow micropylar portion of sac has lengthened and 
increased somewhat in width; side opposite raphe has pushed out into integu- 
ment, giving an asymmetrical sac; 162. 
1G. 56.—Outline sketch of vertical section of embryo and accompanying 
endosperm tissue; embryo is differentiated into radicle, hypocotyl, and 2 
cotyledons; X 162 
