Question

The whole bract present below the inflorescence of sunflower is:
A. Epicalyx
B. Spathe
C. Involucel
D. Involucre

Answer 1

Hint: Inflorescence is a group or a cluster of flowers or arrangement of flowers on the floral axis. The stalk which bears this inflorescence is known as peduncle. The inflorescence present in the sunflower plant is the capitulum or head inflorescence.

Complete answer:
To solve the given question, we must be well aware of the various inflorescences.
 The capitulum or the head inflorescence has a flat spherical top. It is a dense racemose inflorescence.
Many sessile flowers are present on a common receptacle. These flowers are arranged in acropetal arrangement. The outer flowers are more mature as compared to the inner flowers.
This type of inflorescence is usually found in the members of the Compositae or Asteraceae family.
Sunflower also has this inflorescence where the clusters of bracts form an involucre.

Now, since we know about the inflorescence present in the sunflower, hence the correct answer to the question is involucre.

Additional information : Epicalyx is the extra whorl outside the calyx. Spathe is the large bract which encloses the flower.

Note: Sunflower belongs to Order Asterales and Family Asteraceae.It must be noted here that sunflower consists of a head or a capitulum which is surrounded by bright yellow coloured ray florets on the outside and the disc florets on the inside. The ray florets are sterile. The two of these florets are arranged in a spiral fashion.