1918] DUDGEON—RUMEX CRISPUS 419 
8. RorH, Franz, Die Fortpflanzungsverhiltnisse bei der Gattung Rumex. 
Diss. Bonn. pl. 1. 1907. 
9. STRASBURGER, EpuarpD, Die Angiospermen und die Gymnospermen. 
Ricca Sek: (pp. 3-0). 
, Die Apogamie der Husichenitien: und allgemeine eu 
die sich aus ihr ergeben. Jahrb. Wiss. Bot. 41:88-164. pls. 1-4. 10 
EXPLANATION OF PLATES XVII-XIX 
Figs. 22-75 were all drawn at an initial magnification of 1460, with the 
pines air of figs. 26 and 60, which were X 4400; all figures have been reduced 
one- 
es 22—Longitudinal section of young nucellus, showing archesporial cell 
terminating a definite axial row. 
IG. 23.—Archesporial cell divided into primary wall cell and megaspore 
mother cell. 
Fic. 24 Silos uoie with 2 megaspore mother cells, both in prophase of 
heterotypic mitos 
«. 25.—Me. oa pore mother cell in prophase of heterotypic mitosis; wall 
cells have divided periclinally. 
Fic. 26.—Diakinesis in megaspore mother cell, sei 32 pairs of chromo- 
somes, the haploid number; reconstructed from 3 s 
Fic. 27.—Spindle of heterotypic mitosis in Jeet aioe cell; plas- 
molysis we possibly indicate initial stage of degeneration. 
Fic. 28.—Normal tetrad of megaspores. 
Fic. —Early degeneration of outer 3 megaspores of tetrad. 
Fic. 30.—Inner cell has preceded outer in homoiotypic mitosis. 
Fic. 31.—Early degeneration of functioning megaspore 
Fic. 32.—Degeneration of functioning megaspore at a slightly later stage. 
Fics. 36, 37.—Degeneration of fully enlarged functioning megaspores. 
Fic. 38.—Normal 2-nucleate stage of embryo sac. 
Fic. 39.—Early stage in degeneration of embryo sac in 2-nucleate stage. 
Fics. 40, 41.—Same, more advanced. 
Fic. 42.—Normal 4-nucleate stage of embryo sa 
Fic. 43.—Degeneration of embryo sac in padeas stage. 
_ Fic. 44.—Normal 8-nucleate stage of embryo sac just beginning mature 
— 
45.—Degeneration of embryo sac in aires stage. 
Fre. 46.—Normal fully developed embry 
Fic. 47.—Fully developed nase’ sac in eed degeneration, appar- 
ently after a long wait for fertilizatio 
Fic. 48.—Transverse section of miner of a young anther, showing 
archesporia cells. 
9.—Archesporial cell divided into primary parietal cell and primary 
‘eicecapiben anak cell. 
