Haustorial Behavior of Embryo Sac
There are instances in which the entire embryo sac may grow beyond the ovular tissue. The central cell may also form multicellular projections from micropylar and chalazal ends which may penetrate into the carpellary tissues and function as haustoria. In the family Loranthaceae which is characterized by semi-parasitic plants, the embryo sacs are usually highly elongated in one plant of this family. Moquiniella rubra the tip of the embryo sac has been observed to enter the style, touch the stigma and even grow down downwards. The maximum length of such embryo sacs is about 48 mm.