Within a framework of the emerging ecological (rather than merely systematic) content of the concept ‘mistletoe’, various observations are presented on embryo and seedling structure of the Santalacean mistletoes, i.e., Phacellaria and the ‘Henslowia’ complex of genera. An attempt is made to interpret, and to extrapolate from, observations on gamocotyly and embryo reduction in the light of certain parallel evolutionary developments in Eremolepidaceae, Loranthaceae, and Viscaceae. It is suggested that cryptocotyly and primary haustoria, and consequently unitunicate radicular apices and adventitious shoot generation from the haustorial disk and/or endophytic system, have evolved in a number of Santalacean mistletoes.