5o6 
AMERICAN JOURNAL OF BOTANY 
[Vol. 8 
DESCRIPTION OF FIGURES 
Plate XXV 
Figs. 1-4. Fertilized egg and filamentous stage of the proembryo. X 150. Figure 
I, 65 hours after pollination; figures 2, 3, 332 hours, figure 4, 284 hours after pollination. 
Figs. 5-8. Development of the bilaterally symmetrical embryo. X 150. Sagittal 
sections. Figure 5, 294 hours after pollination; figure 6, 428 hours, figure 7, 480 hours^ 
figure 8, 600 hours after pollination. 
Figs. 9-10. Formation of the lateral growing point, sagittal sections. X 150. 
Figure 9, 480 hours, figure 10, 600 hours after pollination. 
Figs. 11-12. Origin of the sheath and of the first leaf, sagittal sections. X 75- 
Figure 11, 576 hours, figure 12, 648 hours after polhnation. 
Plate XXVI 
Figs. 13-20. Stages in the development of the vascular strands and of sheath and 
leaf. Figures 13, 19, frontal sections; figures 14, 15, 17, 18, 20, sagittal; figure 16, inter- 
mediate. X 30. Figures 13, 14, 648 hours, figure 15, 576 hours after pollination; figure 
16, age unknown; figure 17, 762 hours, figures 18, 19, 20, 888 hours after polhnation. All 
are reconstructions from several serial sections. Figure 16 shows a case where one of the 
loops has failed to develop. The partial suppression of one loop was observed on several 
occasions. 
Fig. 21. Surface view of embryo showing the sheath and the first leaf. The shapes 
of the cells at the margin of the sheath and in the leaf and surrounding portion of the 
cotyledon have been indicated. X 90. 
Fig. 22. Front view of sheath. The cotyledon was split sagittally from the rear 
and the sheathing base was spread out on the slide. All cut edges indicated by broken 
lines; vascular bundles by dotted lines. X 9. 
Fig. 23. Transverse section of cotyledon and sheath. This shows the positions of 
the vascular bundles and of the first leaf. X 75. 
Figs. 24, 25. Seedlings, about two weeks after germination. These show the length 
of the sheath. In figure 24 the seed has been entirely removed from the absorbing coty- 
ledon, but in figure 25, although the seed coats have been removed, the endosperm is intact. 
Vascular bundles indicated by dotted lines. X 3. 
"5"' suspensor, "i?" radicle, " Sh" sheath, "L" first leaf, "C" cotyledon, 
endosperm. 
