452 ‘* BOTANICAL GAZETTE [DECEMBER 
EXPLANATION OF PLATE X 
All figures were drawn with the aid of an Abbé camera lucida, and show a 
magnification of 900 diameters. The following abbreviations are used: a, 
antipodals; d, daughter cell of megaspore mother cell; e, endosperm nucleus; 
m, megaspore; pt, pollen tube; s, synergid; co’, male deceu 
Fic. 1.—First division in the megaspore mother cell. 
Fic. 2.—Daughter cells resulting from division of megaspore mother cell. 
Fic. 3.—Two megaspores formed by the division of the chalazal daughter 
cell, and the undivided micropylar daughter cell. 
Fic. 4.—Micropylar daughter cell dividing; the only case observed. 
Fic. 5.—Young two-nucleate sac; spindle fibers still present; no separating 
wall; abortive megaspore and daughter cell represented by two deeply stain- 
ing masses. 
Fic. 6.—Two-nucleate sac after formation of central vacuole. 
Fic. 7.—Four-nucleate sac. 
Fic. 8.—Division to form eight nuclei. 
Fic. 9.—Eight-nucleate sac. 
Fic. 10.—Fusion of polar nuclei. 
Fic. 11.—Division to form eight nuclei; the two chalazal spindles show a 
tendency to become parallel to each other. : 
Fig. 12.—Metaphase of a similar division; the two chalazal spindles 
have mete to form a single large spindle. 
Fic. 13.—Later stage; the division es the coalesced chalazal spindles lagging 
behind ek of the micropylar ones. 
1G. 14.—Telophase of a similar division; wall appearing on the fibers of 
the spindle formed by coalescence. 
15.—Wall complete; the nucleus cut off in the base of the sac beginning 
to disorganize; its sister nucleus free in the cytoplasm with the polar nucleus 
of the micropylar group. 
Fic. 16.—Sac containing bwo-aled proembryo, endosperm nucleus, dis- 
organized cell in base, and pollen tu 
Fic. 17.—Nearly equal division of megaspore mother cell; wall formed on 
the spindle fibers. 
Fic. 18.—Later stage; the wall has disappeared and a central vacuole has 
formed. 
Fic. 19.—Four megaspore nuclei with evanescent walls. 
Fic. 20.—Four megaspore nuclei; the walls have disappeared. 
Fic. 21.—Four megaspore nuclei dividing to form the eight nuclei of the 
sac; megaspore wall still evident in chalazal end. 
Fic. 22.—Sac in which the chalazal megaspore wall has persisted. 
Fic. 23.—Later stage; walls in micropylar end complete. 
Fic. 24.—Double fertilization in a typical eight-nucleate sac. 
: Fic. 25.—Sac containing young embryo; éndosperm and antipodal nuclei 
