Question

“Gemmae” are multicellular green structures for vegetative propagation. These are found in gemma cups in

• A. Riccia thallus
• B. Marchantia thallus
• C. Funaria protonema
• D. Fern prothallus

Hint:

NCERT Fact: Marchantia + Gemma Cups + Gemmae is a very frequently asked biology combination. Always associate vegetative reproduction through gemmae with Marchantia.

Answer 1

The Correct Option is B

Concept: Vegetative reproduction is a form of asexual reproduction in which new individuals develop from vegetative structures of the parent plant. In bryophytes, particularly liverworts, specialized structures called gemmae are produced for vegetative propagation. Gemmae are:
• Small multicellular bodies
• Green in colour
• Haploid in nature
• Produced inside cup-shaped structures called gemma cups When rainwater splashes the gemmae out of the cup, they disperse and develop into new plants.

Step 1: Analyze Option (A) Riccia thallus
Riccia is a liverwort. Although Riccia reproduces vegetatively through fragmentation, it does not characteristically possess gemma cups containing gemmae. Therefore, this option is incorrect.

Step 2: Analyze Option (B) Marchantia thallus
Marchantia is a well-known liverwort. Its dorsal surface bears cup-shaped structures known as: \[ \text{Gemma Cups} \] These gemma cups contain numerous multicellular green gemmae. When dispersed by rain, each gemma develops into a new Marchantia plant. Thus, Marchantia is the classic example associated with gemma cups. Hence, this option is correct.

Step 3: Analyze Option (C) Funaria protonema
Funaria is a moss. Its protonema is a filamentous juvenile stage that can participate in vegetative propagation. However, gemma cups are absent in Funaria. Therefore, this option is incorrect.

Step 4: Analyze Option (D) Fern prothallus
The prothallus is the gametophytic stage of ferns. Although it bears sex organs such as antheridia and archegonia, it does not possess gemma cups. Therefore, this option is incorrect. Final Conclusion: Gemmae are multicellular green structures present inside gemma cups of Marchantia and help in vegetative propagation. Hence, \[ \boxed{\text{Correct Answer}=(B)\ \text{Marchantia thallus}} \]