What is the thalamus or receptacle in a flower?

• A. Swollen, spherical-shaped or conical upper part of pedicel from where the flower arises
• B. A stem that connects flower to stalk
• C. The tissue that forms the ovary
• D. A leaf-like organ at base of inflorescence

Answer: (A)

In flowers, the thalamus, or receptacle, is the swollen, expanded end of the floral axis where the flower attaches. It acts as the base or platform on which all the floral organs—sepals, petals, stamens, and pistil—are arranged. This makes the description of being a swollen, spherical-shaped or conical upper part of the pedicel from which the flower arises the best fit, because it directly identifies the part that bears the floral organs. The ovary is a distinct organ that develops inside the flower and sits in relation to the receptacle, but it is not the receptacle itself. A stem connecting the flower to the stalk describes the pedicel or peduncle, not the receptacle. A leaf-like organ at the base of the inflorescence refers to a bract, which is a different structure.