Loranthaceae Juss. (Santalales) is a widespread family of root and stem hemiparasitic plants with a staggering diversity in floral morphology, especially in the Neotropics. The family has species that range in floral size from small (a few millimeters long, pollinated by insects), to medium (3-5 cm long, pollinated by insects) to large (over 10 cm, pollinated by birds). The family exhibit atypical features, including a modified calyx, an extreme ovule reduction lacking integuments and a properly formed nucellus, an unusual development of the embryo sac into a placental-ovular complex called the mamelon, the embryo sac migration to the style and stigma, ectopic fertilization, and the repositioning of the proembryo(s) to the ovarian region. Fruits, traditionally described as berries, develop from inferior ovaries that are fused to the hypanthium, hereafter called dispersal units. Each unit contains viscin, a substance that facilitates dispersal and adhesion to the host plant prior to the formation of haustoria. Perhaps one of the most peculiar features described in the genus Psittacanthus is the occurrence of embryo dimorphism, with embryos forming two leafy laminar cotyledons, or 5-12 massive and prismatic cotyledons. Finally the absence of endosperm has also been described for both  Aetanthus and Psittacanthus. This work revisits the interpretations and assesses the homology of these unusual features, by undertaking a comparative developmental approach. Samples of Aetanthus colombianus A.C. Sm., Gaiadendron punctatum (Ruiz & Pav.) G. Don., Passovia pedunculata (Jacq.) Kuijt., Psittacanthus longerectus Roldan-Palacios & Alzate-Guarín, and Tristerix secundus (Benth.) Kuijt. were collected and fixed in 70% EtOH. Flowers to preanthesis to late anthesis and developing fruits were dehydrated in a series of absolute ethanol, followed by Ethanol-Histochoice (50-50%), ending in Paraplast Plus. Specimens were serially sectioned at 10 µm with a Leica rotary microtome, stained with safranin-astra-blue, and mounted in Entellan. Slides were observed in a Leica DM500 bright field microscope and photographed with a Leica ICC50W camera.  Our results indicate that: 1) The limits of the carpellary tissue remain detectable during ontogeny while the ovules are extremely reduced, 2) The epicarp (extracarpellary tissue) in all species undergoes profound tissue modifications forming the fleshy portion of the dispersal unit and the viscin;  3) There is a fully formed endosperm accompanying embryo development  in Aetanthus and Psittacanthus. This project lays the morphoanatomical foundations necessary to carry out evo-devo studies to identify the genes responsible for such modifications and for the occurrence of successful fertilization in the absence of normal ovules.