As early as the three-celled stage of embryogenesis, the basal cell of chickweed, Stellaria media, is larger than the other embryonic cells and contains large differentiating plastids, microbodies, and wall ingrowths of the transfer cell type at the micropylar end of the cell. Subsequent development produces a suspensor with unique plastids, microbodies, and extensive profiles of dilated endoplasmic reticulum not found in the embryo proper. The suspensor plastids, which appear to be different from any other plastids previously described on the ultra-structural level, are large and contain two types of tubules and electron-translucent inclusions. Plasmodesmata occur in the end walls but not in the side walls of the suspensor cells. It is suggested that the suspensor of chickweed is involved in important, possibly essential, translocation and metabolic activities during early embryogenesis.