Question

Capitulum is heterogamous in
A. Helianthus
B. Cichorium
C. Lactuca
D. Sonchus

Answer 1

Hint: Pseudanthium in Greek known as the false flower which are also called as flower head , composite flower or the capitulum. In this several groups of flowers are grouped together and are seen as a single flower like structure.

Complete Answer:
- Capitulum is an inflorescence which is composed of strongly packed flowers or florets which have no stalks and come up on a flattened axis, all of them at the same level. The capitulum is enclosed or subtended by an involucre of bracts giving it the form of a single flower. Capitula are characteristic of the Compositae.
- In Capitulum or head inflorescence the head is a short thick point in which the flowers are borne directly on a broad, flat peduncle, providing the inflorescence the look of a single flower.
- Heterogamous when in a capitulum the florets of the beam are also neutral or female and those of the disk male . Having two types of flowers, which is as in Compositae the florets of the beam may be neuter or unisexual and in those of the disk hermaphrodite.
- In Helianthus the capitulum is heterogamous that means it bears flowers which are sexually dissimilar. In Helianthus, the outer flowers generally have a well developed zygomorphic corolla and the inner disk flowers normally have actinomorphic corolla.
- The inner disk flowers are usually complete flowers, that is they must have sepals, petals, at least one stamen and at least one pistil and the ray flowers are in general sterile. So we can conclude that the capitulum seen in Helianthus are heterogamous.

Therefore the correct answer for this question is option A) Helianthus.

Note: The capitulum which is an important taxonomical finding which defines the daisy family which is the largest flowering plant group. They are composed of numerous tiny florets and generally in the family of Asteraceae.