ABSTRACT The developmental anatomy of fruit and seed in Cassytha filiformis is studied. The fruit is a drupe enclosed by the enlarged, inflated, succulent calyx tube. The ripe pericarp consists of three layers: outer epidermis, inner epidermis of palisade and a layer of sclereids above the inner epidermis. The mature seed coat is formed entirely by the testa. The outer epidermis of the testa consists of large cells with unlignified walls, and the inner epidermis acquires characteristic helical thickenings. On the basis of fruit and seed characters it is suggested that the genus Cassytha rightly belongs to the family Lauraceae.