108 COMPARATIVE EMBRYOLOGY OF THE RUBIACEAE 
FIG. 17. pod view of chromosomes (12) metaphase, second division. 
Fic, 18. Anaphase, second division 
Fic. 19. Polar view anaphase, Mad division. 
Fic, 21, a, 6. Chromosome ipie prophase, first embryo-sac-mother-cell division, 
Fic. 22. Early anaphase, first embryo-sac-mother-cell division. 
Fic. 23. Telophase, first ten embryo-sac-mother-cell. 
PLATE Io 
Fics. 1-6. Rubia tinctoria 
Fic vpn. ovule before the integument has started to grow. Two archesporial 
cells are ber 
Fic. 2. یب‎ -cells of megaspore mother-cell in division. 
Fic. 3. Embrvo-sac with four cells. 
Fic. 4. Embryo-sac with two cells. At e s a second embryo-sac is seen contain- 
ing but one nucleus. Above, in the archesporial cavity are several megaspore nuclei. 
. Embryo-sac, defaitive, 
Fic d Embryo. The embryo proper is very young, consisting of 13 cells. The 
suspensor is exceedingly well developed as a haustorial organ 
Fics. 7-22. Crucianella 
Fic. 7. C. gilaniva. Young ovule, showing archesporium of very large cells, and 
the nutritive cells at the chalazal end. 
Fic. 8 ughter-cells, at close of first division. 
Fic. 9. Megaspores formed by two divisions of the d cells. The end 
cell has become the embryo-sac cell and has begun to develop as 
3 Fic, 10. C. herbacea, Ovule, in outline, سر ین‎ its typograp Chalazal nu- 
tritive tissue and megaspore masses above and an embr yo-sac An both partially 
surrounded by the specialized nutritive tissue derived bon ۳ integument. 
Fic. 11. Megaspore masses (seen in fig. ro), enlar, 
Fic. 12. een (seen in fig. zo), enlarged, re antipodal nucleus only. 
Polar nuclei not yet fus 
Fic. 13. Nutritive eset tissue from another ovule; archesporium and 
chalazal yep cells above; emb below. 
IG. I4. A trinucleate cell from توت‎ nutritive tissue. 
Fic, 1 » Embryo showing, in particular, the suspensor. 
Fics. 16-22.  Crucianella macrostachya 
Fic. 16. Two embryo-sac-mother-c ells. The one on the right with a E 
e first division; on the left two spindles of the second division. 
Fe 1 Anaphase and telophase of the second divi sion. 
i 19, 
in mitosis, 
+ 22, do embryo-sac ( with two nuclei) and four sets of megaspores. m. 
of one set are in mitosis, 
