FISHER: SEED DEVELOPMENT IN PEPEROMIA 241 
Fics. 37-43. Piper tuberculatum 
Fic. 37. Longitudinal section of. young ovule, showing primary archesporial 
cell; integuments not yet started. 670. 
Fic. 38. Longitudinal section of a slightly older ovule, in which the primary 
archesporil cell has divided to the definitive archesporial cell and the parietal cell. 
aes 1G. Longitudinal section of ee older ovule, showing definitive arche- 
sporial cell or embryo sac mother-cell; the parietal cell has divided forming tapetum 
four cells thick. 70. 
Longitudinal section of nucellus, showing two-nucleate embryo sac. 
FIG. 40. 
X 670. 
Fic. 41. Same as preceding in outline with addition of integuments. XX 220. 
Fic. 42. Long itudinal section of four-nucleate embryo sac, showing the linear 
X 670. 
arrangement of the n 
FIG. 43. triples’ section of eight-nucleate embryo sac, the two polar 
670. 
nuclei tine to form the endosperm nucleus. 
