Double fertilisation is reported in both castor and groundnut but their mature seeds are different in terms of endosperm. The primary endosperm nucleus formed after fertilisation divides mitotically without cytokinesis to initiate the formation of endosperm. At this stage, the endosperm is called free nuclear endosperm.
Then, cell wall formation occurs and the endosperm becomes cellular type. The number of free nuclei formed before cellularisation varies greatly. Endosperm may be completely utilised by the developing embryo before the maturation of seeds as in groundnut. Such seeds are called non-albuminous or non-endospermic seeds.
When a portion of endosperm remains in seeds and is used up during seed germination, such seeds are called albuminous or endospermic seeds, e.g. castor.