The Development of the Embryo Sac of Smilacina stellata

Abstract

1. The mother cell of Smilacina stellata divides twice to form four nuclei, which are separated by walls to form four megaspores. 2. The division walls and plasma membranes which separate the four nuclei are absorbed, so that the four reduction nuclei occupy a common cell cavity. 3. Each of these four nuclei divides again, and the resulting eight nuclei organize to form the embryo sac. 4. It is plain from these facts that we have four individual megaspore cells combining to form one embryo sac or gametophyte in Smilacina stellata. 5. It is thus strongly suggested that in the embryo sac of the lilies the first four nuclei are morphologically megaspores. 6. In Smilacina racemosa the outer daughter cell of the heterotypic division develops into the embryo sac, although the long persistence of the two nuclei formed by the division of the inner heterotypic nucleus might suggest that they should be considered a part of the embryo sac. Smilacina racemosa shows temporary cell division at the close of the homeotypic division, agreeing in this respect with Smilacina stellata.