110 COMPARATIVE EMBRYOLOGY OF THE RUBIACEAE 
Fics. 37-42. Embryo-sac tetrad division. 
Fics. 37, 38. Prophase, first division. 
Fics. 39, 40. Early anaphase, first division 
Fic. 41, Separating chromosomes, anaphase, first division. 
Fic. 42. Prophase, second division. Perinuclear radiations. 
Fic. 43. First embryo-sac division. 
Fic. 44. Separating chromosomes of the first embryo-sac division. 
PLATE 12 
Fics. 1-12. Diodia Virginiana 
Fic. 1. Basal partition with nucelli. 
IG. 2. Ovule with one-celled embryo-sac. 2, a’, branches of vascular bundle, 
Fic, 3. Part of young ovule, the integument commencing, showing archesporium. 
Fic. 4. One-celled embryo-sac in migration. The remaining megaspores seen 
above following the embryo-sac 
IG. 5. A similar condition in another ovule. 
Fic. 8. Ovule with definitive embryo-sac, Horen the relation of parts. 2,4”, 
branches of vascular tissue. The isolated cells have appeared which later form a con- 
tinuous ری‎ as seen in fig. 9, sp 
Fic. 9. Older ovule. 
Fics. fia 11, I2. The antipodal end of three embryo-sacs showing the number 
and arrangement of antipodal cells in each. 
FIGS. 13-1 é Diodia teres 
Fic. 13. Basal partition and young nucelli. 
Fic, 14. Somewhat older condition ar the strophiole (s¢) beginning to de- 
m 
15. Archesporium. One large functional megaspore mother-cell flanked by 
a nave one. 
Fic. 16. Young ovule with archesporial cell in ‘its second division ; strophiole 
well marked. 
Fic. 17. Second division of the megaspore mother-cell. 
PLATE 13 
Fics, 1-10. Diodia teres 
Fic. 1. Young ovule, with one-celled embryo-sac. The strophiole is seen to close 
the mieropyle, 
Archesporium showing the large, functional megaspore, and the tie 
sister مش تست بو‎ to separate. The arrow indicates position of micropyle. 
Fic. 3. Embryo-sac cell وج‎ ; at the base are seen two nutritive cells. 
en 4. Two-celled embryo-sa 
G. 5. Embryo-sac. 
IG. 6. Embryo-sac after fertilization containing a one-celled embryo. The anti _ 
normal. 
podals are still 
f 
Fic. 7, Hi. ovule in longitudinal section containing the embryo-sac shown inde 。 
tail in Fig. 
Fic, 8. on older condition with more advanced endosperm and embryo. 
Ri detail, 
10, More advanced embryo, showing the suspensor after stretching. 
