Question

Monadelphous androecium occurs in
A. Pea
B. Hibiscus
C. Brassica
D. Helianthus

Answer 1

Hint: Monadelphous is a condition when all the filaments unite and form a tube around the female gynoecium.
Androecium is the male part of the flower i.e stamens.
Androecium is of 6 types namely— Monadelphous, Pseudomonadelphous without basal fenestration, Diadelphous, Pseudomonadelphous with basal fenestration, Reduced diadelphous, Androecium with free stamens.

Complete answer:
Monadelphous is a condition when all the filaments unite and form a tube around the female gynoecium. The tube that is formed is called as staminal tube. It is seen in hibiscus, cotton, hollyhock, ladyfinger etc.
Androecium is the male part of the flower i.e. stamens.
Androecium is of 6 types namely—
Monadelphous
Pseudo Monadelphous without basal fenestration
Diadelphous
Pseudo Monadelphous with basal fenestration
Reduced diadelphous
Androecium with free stamens
Option A. Pea has a diadelphous androecium i.e. all the stamens unite to form two bundles
Option B. Hibiscus has a Monadelphous androecium.
Option C. Brassica is tetradynamous i.e. two lateral stamens are small and four median stamens are large.
Option D. In case of helianthus there are five separate stamens which unite to form a tube around the style. It is attached superiorly and inferiorly.

So the correct answer is option B. Hibiscus.

Note:
Pea has a diadelphous androecium i.e. all the stamens unite to form two bundles. Hibiscus has a Monadelphous androecium. Brassica is tetradynamous i.e two lateral stamens are small and four median stamens are large. In case of helianthus there are five separate stamens which unite to form a tube around the style. It is attached superiorly and inferiorly.