Embryology of Certain Ranales

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Abstract
Based on previous investigations of the embryology in 5 families of the Ranales, the group as a whole presents 2 distinct types of embryo development. In the Magnoliaceae, Ranuncu-laceae, and Berberidaceae, the embryo is at first an un-differentiated, pear-shaped body with a massive suspensor. The cotyledons arise symmetrically from the distal end of the embryo as 2 independent structures. In the present investigation the embryology of Magnolia grandiflora and Cimicifuga racemosa is seen to conform to this plan. In the Nymphaeaceae and Ceratophyllaceae, a suspensor is usually lacking, the cotyledons arise from a common primordium, and the mature embryo is asymmetrical. Furthermore, in the Magnoliaceae, Ranunculaceae, and Berberidaceae, the endosperm consists in its early development of free nuclei, while in the Nymphaeaceae and Ceratophyllaceae the endosperm in nearly all cases is cellular from the beginning. There seems to be some basis for the suggestion that the Nymphaeaceae and Ceratophyllaceae be placed in the Monocotyledoneae.