1git] SHARP—PHYSOSTEGIA d 225 
EXPLANATION OF PLATES VI AND VII 
All figures were drawn with the aid of an Abbé camera lucida, have a cor- 
responding orientation, and show magnifications as follows: figs. 1, 11, 13-17, 
X 215; figs. 2-5, 9, X 462; figs. 6, 7, 10, 12, X 385; fig. 8, X81; figs. 18, 19, X45; 
fig. 20, X25. The following abbreviations are used: a, antipodals; e, egg; 
el, endosperm lobe; em, embryo; end, endosperm; f, fusion nucleus; h, haus- 
torial antipodal; 7, integument; m/l, micropylar lobe; , nucellus; 0, ovary 
wall; p, polar nucleus; pf, pollen tube; s, synergids; v, vascular supply. 
PLATE VI 
Fic. 1.—Young ovule with archesporial cell nucleus in synapsis. 
Fic. 2.—Four megaspores; the division to form the two micropylar ones 
is delayed. 
Fig. 3.—Four megaspores; the innermost one much enlarged, the other 
three disceusnizing. 
Fig. 4.—Two-nucleate embryo sac. 
Fic. 5.—Four-nucleate embryo sac. 
Fic. 6.—Eight-nucleate embryo sa 
G. 7.—Mature embryo sac; the — nuclei have fused and the antip- 
odals fae increased in number; one antipodal beginning to differentiate 
as a — cell. 
8.—Ovule with mature embryo sa 
—Triple fusion of male and a nuclei; haustorial antipodal cell 
ees sites antipodals disorganizing. 
IG. 1o—First division of endosperm nucleus. 
IG. 11.—Daughter nuclei resulting from first division of endosperm 
nucleus; the wall accompanying the division is still in process of formation. 
IG. 12.—Subsequent endosperm divisions, all accompanied by walls. 
PLATE VII 
Fic. 13.—Two-celled proembryo coming into contact with the endosperm; 
false antipodal cell well developed; the other antipodals and the syner- 
gids have degenerated. 
Fic. 14.—Later stage; — formation has ceased eet at the 
narrow portion of the sac in this cas 
Fic. 15.—Chalazal cell of enh divided longitudinally. 
Fic. 16.—Somewhat later stage; the endosperm has extended into the 
micropylar lobe. 
IG, 17.—Later stage of embryo. 
Fic. 18.—Endosperm invading integument; embryo digesting endosperm; 
haustorial antipodal cell and micropylar lobe disorganized. 
Fic. 19.—Later stage. 
Fic. 20.—Section of nearly mature seed; the embryo has used up the 
greater part of the endosperm, which in turn has obliterated nearly all of the 
integument; seed coat formed from the ovary wall (0). 
Pa 
