Both chasmogamous and cleistogamous flowers are present in:

a. Helianthus

b. Commelina

c. Rosa

d. Gossypium

In chasmogamous plants, flowers open at maturity. These flowers are mostly cross-pollinated, though self-pollination may also occur when both male and female reproductive parts are present in the same flower (homogamy). Pollination generally requires external agents like insects or wind. Chasmogamous flowers usually have bright petals and often produce fragrance to attract pollinators. Examples include Convolvulus, Mirabilis, Helianthus, and Catharanthus.

• Self-pollination: Transfer of pollen from anther to stigma of the same flower (autogamy) or to another flower of the same plant (geitonogamy).
• Cross-pollination: Transfer of pollen from anther of one plant to the stigma of a different plant of the same or related species.

Cleistogamous Flowers

In cleistogamous plants, bisexual flowers remain closed and never open. These flowers are self-pollinated and homogamous. They do not require external agents, nor do they have showy petals or fragrance. Examples include Pisum (pea), Lathyrus, and groundnut.

Amphicarpy in Commelina

In Commelina, both types of flowers occur:

• Chasmogamous flowers – Open, aerial flowers.
• Cleistogamous flowers – Closed, underground flowers.

This condition is called amphicarpy, and such flowers are termed chasmocleistogamous. In these, anthers and stigma lie close together; when anthers burst, pollen grains directly reach the stigma.

Examples

• Chasmogamous: Helianthus (sunflower), Rosa (rose), Gossypium (cotton).
• Chasmogamous + Cleistogamous (Amphicarpy): Commelina.

Correct Answer: Option B – Commelina