Question

Find the odd set out.

• A. Stolons, rhizomes, corms
• B. Thorns, bracts, stipules
• C. Pneumatophores, stilt roots, haustoria
• D. Tapetum, pollen grain, endothecium

Answer 1

The correct option is B

Thorns, bracts, stipules

Thorns are hard, rigid extensions of leaves, roots, stems or buds. Bracts are specialized leaf or leaflike parts, usually situated at the base of a flower or inflorescence while stipules are small leaf-like appendages, typically borne in pairs at the base of the leaf stalk. Thorns, stipules and leaf do not belong to a common category.
Stolons, rhizomes and corms are all stem modifications. Rhizomes and corms are stems modified for food storage. A stolon is a horizontal stem running across or just under the ground.
Pneumatophores, stilt roots and haustoria are modified roots. Pneumatophores are respiratory roots found in plants in swampy areas, helping in gaseous exchange. Stilt roots provide additional support to the plant. They are adventitious roots that grow from the base of the stem other than the original roots of the plant. Parasitic plants, like Cuscuta, always grows in association with other plants. The parasitic plant at the point of attachment with the host plant produces some knob like roots known as haustoria which penetrate into the host plant and draws nourishment.
Tapetum and endothecium are wall layers in anthers, pollen grains are the male gametophyte in angiosperms.