The embryo sac is shown ready for fertilization. The egg and synergids are in contact with the outer integument at the micropylar end. The remains of the antipodals may be seen at the chalazal end. × 180.
Fig. 2.—Section through an Ovule of Melilotus alba, about Three Days After Fertilization.
The proembryo, the endosperm, and modifications of the integuments are shown. At this stage the suspensor prominent part of the proembryo, and the endosperm is most abundant around the embryo. The inner integument is being rapidly destroyed, and the outer integument is beginning to form the seed coat, as is indicated by the modifications in the outer layer of its cells, which are elongating and thickening their outer walls. × 33.
Fig. 1.—Section of an Ovule of Melilotus alba after Fertilization.
The stage of development is a little later than that shown in Plate II, figure 2. The embryo is embedded deeply in endosperm tissue. × 45.
Fig. 2.—Section through an Ovule of Melilotus alba after the Embryo is Nearly Half Mature.