Question

What is the inflorescence of marigolds?

Answer 1

Hint: Inflorescence is the arrangement of flowers on the stem. The stalk on which the flower is borne is known as the peduncle. The different families of plants have different kinds of inflorescence. The type of inflorescence is an identifying characteristic of a family. The marigold belongs to the family Asteraceae.

Complete answer:
The arrangement of the flower on the stem is called an inflorescence. The inflorescence is divided into two types on the basis of its arrangement around the main axis- racemose and cymose.
Cymose- In this the younger flowers are present at the base and the older ones at the top. Example Drosera, hibiscus

The racemose inflorescence is the type in which the plants grow indefinitely around the axis and the flowers are born in acropetal succession. Such kind of inflorescence is found in the Asteraceae family.
The Asteraceae family is one of the largest flowers bearing families. Examples of such plants are marigold, sunflower.

The marigold peduncle is short and flat. It bears several flowers in a cluster that look like a single flower. The flowers are known as the florets and are arranged in a centripetal manner. In this, the outer florets are longer and are called ray florets and the inner is flat known as disc florets. This kind is known as head or capitulum. The figure below shows the head or capitulum type of inflorescence.

Note: Apart from the two types, the inflorescence varies greatly because of the insects which feed on the nectar. Also, the temperature affects the inflorescence that is late bud formation in case of higher temperature. The herbivores also affect the inflorescence greatly. Several plants show inflorescence which is an intermediate type.