Plant Body in Thalloid Plants

Thalloid plants are characterized by their simple and undifferentiated plant body, which is known as a thallus. The thallus is a flattened structure that lacks true stems, leaves, and roots. It is typically a multicellular and photosynthetic tissue that performs various functions in the plant.

Examples of Thalloid Plants

1. Funaria: Funaria, commonly known as the moss, is a thalloid plant that belongs to the Bryophyta division. Its plant body consists of a protonema and a gametophyte. The protonema is a filamentous structure that develops from the spore and eventually gives rise to the leafy gametophyte. The gametophyte, which is the dominant phase in the life cycle, is a leafy structure that contains rhizoids for anchorage and absorption of water.

2. Sphagnum: Sphagnum, also known as peat moss, is another example of a thalloid plant. It belongs to the Bryophyta division and has a characteristic bog habitat. The plant body of Sphagnum consists of a protonema and a gametophyte. The gametophyte is a cushion-like structure that can hold large amounts of water. Sphagnum plays a crucial role in the formation of peat bogs and serves as a habitat for various organisms.

3. Salvinia: Salvinia is a floating aquatic fern that belongs to the Pteridophyta division. It has a thalloid plant body that floats on the water surface. The plant body of Salvinia consists of a branched rhizome that bears small, floating leaves. The leaves have a unique structure that allows them to repel water, providing buoyancy to the plant.

4. Marchantia: Marchantia is a thalloid liverwort that belongs to the Marchantiophyta division. Its plant body consists of a dichotomously branched thallus. The upper surface of the thallus bears air chambers, which facilitate gas exchange. The lower surface contains rhizoids for anchorage and absorption of water.

Conclusion

Thalloid plants, such as Funaria, Sphagnum, Salvinia, and Marchantia, have a simple and undifferentiated plant body known as a thallus. These plants lack true stems, leaves, and roots and instead have a multicellular and photosynthetic thallus that performs various functions.

Option (D) Marchantia is the correct answer.