Abstract: We observed the course of megasporogenesis and the development of the female gametophyte of Thellungiella halophila to study the relation between the development stages and the morphological characteristics of flower bud, flower and fruit. The ovary is composed of 2 carpels where a parietal placentation is formed, on which many campylotropous ovules grow. The ovule is bitegminous and tenuinucellate. The archesporial cell lies under the nucellus epidermis, which develops into a functional megasporocyte. The megaspore tetrad is linear. The chalazal megaspore develops into an embryo sac of the polygonum type.