es jaui 
14 ARISAEMA TRIPHYLLUM 
division and endosperm from the free nucleate stage up to twenty 
cells. 
i The first division of the fertilized egg results in the formation 
of-a small embryo cell and a large suspensor cell (PLATE 1, FIGS. 7, ; 
11). The suspensor cell may divide at least once immediately 
(PLATE 1, FIGS. 12, 13), and later undergoes several divisions (TEXT 
FIGS. 13-19). The development of the complex suspensor shown 
oN 
Fics. a3, 14. Embryos with two growing regions newly differentiated. The 
section in FIG. I3 is just a little diagonal. X 65 
Fics. 13-18. Embryos of increasing age, showing arrangement of cells and 
development of suspensor. 13, 14, 17, X 65; 15, 16, 18, X 165. 
Fic. 18. An embryo with the suspensor group pushed into the broken down 
nucellar cap, NC. X 165 
Fic. 19. An unusually complex suspensor group and an embryo deeply buried 
in the endosperm. X 65. is and FIG. 17 show the thickening of the suspensor y 
cell walls 
T lee ee N, 
Fic. 20. Cross section of an embryo similar to that in FIG. 16. X 165 
Fic. 21. A diagrammatic longitudinal section of an almost mature embryo. 
XAS: 
Fic. 21a. Detail drawing of plumule of FIG. 21. X 65. 
FO ee et ee ee PCy eh oe 
does not take place until the embryo has assumed asomewhat globu- ; 
lar form, as in TEXT FIG. 15, where two or three divisions have 7 
occurred and the resultant cells enlarged. As growth of embryo 2 
and endosperm proceeds, the suspensor cells form thick walls, and 
become closely connected with the aleurone layer of the endo- 
