Question

Which among the following is a rootless plant?
A) Nymphaea
B) Sagittaria
C) Ceratophyllum
D) Vallisneria

Answer 1

Hydrophytes are those plants that live in water. Some of the hydrophytes remain fully submerged underwater like hydrilla, Vallisneria, , etc. In some of the hydrophytes, most of their plant body parts remain under the water like lotus, trapa, etc.

Complete answer:
Nymphaea - Nymphaea is a rooted hydrophyte that has floating rounded leaves. They reproduce by root tubers.
Sagittaria - Sagittaria is a rooted hydrophyte with submerged, floating, and aerial leaves. The plant produces edible underwater food Tuber. Their roots are harvested by hands, eaten, and cooked.
Ceratophyllum - Ceratophyllum is a rootless hydrophyte commonly known as cocktails and hornworts. They are completely submerged plants with 1-3 m stems in length. They cannot tolerate drought. They produce rings of bright green that are located at intervals along with the nodes of the stem.
Vallisneria - Vallisneria is a rooted hydrophyte. They are completely submerged plants that are spread by runners. Their leaves arise in clusters from their roots and have rounded tips and define raised veins. The female white flowers grow to the water surface on very long stalks. The male flowers grow on short stalks, get detached, and float to the surface of the water.
Thus, option C is the correct answer.

Note: Hydrophytes or macrophytes are the aquatic plants that are adapted to live in aquatic environments, freshwater or saltwater. These plants require a specific adaptation for living submerged or at the surface of the water. This plant can only grow in water or soil.