1906] ~ COOK—CUBAN NYMPHAEACEAE 301 
Fic. 10. Embryo sac of C. piauhiensis, showing two-celled embryo and 
nucellar tube. The endosperm nucleus has divided and one daughter cell entered 
the tube (nin), while the other has remained in the sac and undergone first 
division (end). 
Fic. 11a. Embryo sac and mature nucellar tube of C. piawhiensis with 
spherical embryo; the thin endosperm filled the sac at this time. 
Fic. 11b. Cross-section of tube of rza at smallest part. 
Fics. 12-19.. Nymphaea advena(?). 
Fic. 12a. Two-celled embryo with daughter nucleus of endosperm nucleus 
(en) after first division; same as fig. 8 
Fic. 12b. Nucellar tube nucleus of figs. 8 and 12a. 
PLATE XVII 
Fic. 13a. Section of spherical embryo in octant. stage surrounded by endo 
sperm. : 
Fic. 136. Lower part of the nucellar tube of 1 3a in which the nucellar tube 
nucleus was divided. 
Fic. 14. Mature nucellar tube nucleus. 
Fic. 15. Spherical embryo. 
Fic. 16. Pear-shaped embryo at time of origin of cotyledonary ridge and 
with well-developed suspensor. 
Fic. 17. Cross-section of embryo a little older than that in fig 16. 
Fic. 18. Cross-section of embryo older than that in fig. 17, showing monocot 
character in lower part and dicot character in upper part; 3d, 4th, 6th, r4th, 
Toth, and 24th sections. 
Fic. 19. Cross-section of embryo showing equal cotyledonary lobes (dicot 
characters); rst, 4th, 5th, 7th, 8th, and 15th sections. 
IGS. 20-22. Castalia ampla. 
Fic. 20. Embryo sac and two-celled embryo showing endosperm and nucellar 
tube nucleus (ntn) in sac-like nucellar tube. 
Fic. 21. Older stage of same, showing absorption of nucellar tube and 
nucleus (nin) by endosperm. 
Fic. 22. Spherical embryo with suspensor. 
PLATE XVIII 
Fics. 23-31. Castalia pubescens. 
Fic. 23. Two-celled embryo and endosperm; the endosperm has penetrated 
the upper part of the nucellar tube. es 
Fic. 24. Spherical embryo with suspensor and endosperm, also showing 
elongated nucellus cells in axis of ovule below sac (enc). 
1G. 25. Older stages of the same showing enlargement of sac at right angles 
to the original long axis. 
1G. 26. Young pear-shaped embryo. 
Fic. 27. Longitudinal section of embryo passing through middle of crescent- 
shaped cotyledonary ridge («) and between the points of the same (y). 
