Development of the Female Gametophyte in Hydrobryum griffithii (Podostemaceae)

The development of the female gametophyte in Hydrobryum griffithii is of the Apinagia type. The chalazal megaspore nucleus of the two-nucleate embryo sac completely degenerates, and only the micropylar megaspore nucleus contributes to the four nuclei present in the organized embryo sac. The female gametophyte consists of two synergids, an egg and a haploid central cell. The latter degenerates before the entry of the pollen tube and there is only syngamy. The nucellar cells below the embryo sac organize into a nucellar plasmodium.