106 COMPARATIVE EMBRYOLOGY OF THE RUBIACEAE 
IG. 2. An example in which several megaspores have began migration. In this 
figure and in Fig. 1 may be seen the compressed endodermis 
- 3. Embryo-sac what fusion of the polar nuclei. The different cells have 
now taken on their definite 
Fic. 4. Embryo-sac with one-celled embryo. One synergid remains intact. 
Fic. 5. A still later condition with 11-celled embryo. Antipodals still intact. 
Fics. 6-9. Various embryos in various stages of development. 
Fic. 10. Suspensor, showing و‎ lts most extreme ise ی‎ in this species. 
FIG. 11. Ovule with end 1 ity (seed a 
The — cells which are ‘still wer ما‎ are dawn on he left s 
. Section through the pericarp ی‎ cell layers), integument (one cell "D ; 
and ie. outer cell layer of the endosperm 
Fics, 13-23. Sherardia arvensis. 
Fic, 13. Mass of megaspore mother-cells. 
Fic, 14. Embryo-sac with the migrating embryo-sac-mother-cell. 
Fic. 15. Definitive embryo-sac just previous to fertilization. 
Fics. 16, 17. Egg apparatus and fusing polar nuclei. 
Fic. 18. Two-celled embryo with endosperm. 
Fic. 19. Older maid in dá two regions in the suspensor are evident. The 
basal region ve hausto: 
Fic. 20. Shows a somewhat more developed condition of the ی‎ proper than 
that seen in a 
Fic uspensor of nearly mature embryo. The basal part of the haustorium 
which Due ی‎ ap in the intact endosperm has degenerated. The haustoria of the 
part of the suspensor which lies in the digested endosperm are active. 
Fic. 22. Ovule from which Fig. 21 is taken. 
Fic. 23. Peripheral portion of endosperm showing outer absorbing cells. 
PLATE 7. Galium 
Figs. 1, 2. Galium Mollugo. Two successive stages in the development of the 
nucellus’ 
Fic. 3. Galium recurvum. In this — the archesporium has reached maturity 
and the i en has started its = wth. 
. Galium recurvum 
Fic. A mega: spore-mass just before the migration of the 
مت‎ -mother-cell. 
The ا‎ cells are not yet destroyed. 
Fic. 5. The megaspore mother-cell in migration. 
Fic. 6. Galium Parisiense. 
G. 7. Galium triflorum. 
n. 9 in order to show the 
The two-celled stage of the embryo-sac. 
-sac. The same embryo-sac is shown in 
length ۳ tha long antipodal. 
G. 8. Galium Aparine. An embryo-sac in which the endosperm has begun to 
form a in which the embryo is composed of six cells, 
Galium triflorum. Ovule in longitudinal section showing the proportions 
FIG. ۰ 
the ee. and the relative position of the end of the food-conducting tissue 
the raphe. 
