Abortion of Ovules

Some of the ovules in the one nut did not form embryo sacs, though it was usual to find three to four ovules, in a six-ovulate nut, with sacs. The process of fertilization was not seen, but about the time it should have taken place many of the ovules with fully developed sacs began to abort. In the 1947–48 season, a sparse flowering year for beech in the areas from which the material was collected, most ovules aborted at this stage and it was therefore difficult to find any pro-embryos or embryos. In the 1948–49 season it was usually possible to find one ovule per nut with a pro-embryo or embryo, but the remaining ovules aborted. Amongst other members of the Fagaceae, Quercus may have all the ovules fertilized and any one is capable of forming the seed (Busgen, 1916).

In the process of abortion the embryo sac and any nucellar tissue collapsed leaving the integument intact at first. The Postament appeared to be the last tissue to break down, while the secondary nucleus could be seen until quite late stages of abortion. In the final stages of breakdown the chalazal end of the ovule, together with the strands of vascular tissue attaching the ovule to the placental conducting tissue, could be seen lying on the side of the developing seed where this was present.