In biology receptacle is the swollen basal part of the flower or can also be geared a's the top of the stalk or pedicel. When the stalk of the plant (The part which connects flower to the plant) gets flattened and the other parts of the flower including the 4 whorls (calyx,corolla,androecium,gymnoecium) start that flattened part is called the receptacle.It is the end part of the stalk or pedicel.