The vascular anatomy of the flower shows that the perianth inMacadamia ternifolia F. Muell. is the whorl of sepals, while the corolla has completely disappeared. Thus a dichalmydeous ancestry is suggested for the Proteaceae. The adnation of the stamens to the perianth is of recent origin. The nature of the carpel is discussed in the light of the interpretation of Hunt (1937) regarding the origin of the modern Angiospermic carpel. The structure of the anther is described. The pollen grains contain a tube nucleus and a small generative cell at the shedding stage. The nature and development of the ovule are pointed out. The embryosac develops along normal lines. Fertilization and changes in the ovule after fertilization are described. The nature of endosperm, some stages in the development of the embryo and the parts of the mature seed are dealt with. Several instances of degenerations of ovules and one instance of an abnormal ovule with two nucelli and common inner and outer integuments are recorded.