Question

In Sphagnum, the sporogonium is elevated by a special gametophytic structure known as:

• A. Pseudopodium
• B. Perichaetium
• C. Antheridium
• D. Amphithecium

Hint:

Remember the key difference: In most mosses, the capsule is raised by the \textbf{seta} (part of the sporophyte, 2n). In {Sphagnum}, it's raised by the \textbf{pseudopodium} (part of the gametophyte, n). 'Pseudo' means false, so it's a 'false stalk' because it's not a true seta.

Answer 1

The Correct Option is A

Step 1: Concept Overview:
The question identifies the structure responsible for elevating the mature sporophyte (sporogonium) in the moss genus *Sphagnum*. This elevation mechanism is a defining characteristic of *Sphagnum*.
Step 2: Detailed Explanation:
In typical mosses, the sporophyte develops from the zygote and remains attached to the gametophyte. The sporophyte comprises a foot, a seta (stalk), and a capsule. The seta's elongation, being diploid sporophytic tissue, elevates the capsule to facilitate spore dispersal. However, in *Sphagnum* (peat moss), the seta remains short. Instead, a stalk-like structure develops from the gametophyte tissue of the archegonial branch, located just below the sporophyte's foot, following fertilization. This haploid gametophytic stalk elongates, pushing the entire mature sporogonium upwards. This structure is termed a pseudopodium, meaning "false foot". Considering the other options:

Perichaetium: Modified leaves surrounding the archegonia (female reproductive organs).
Antheridium: The male reproductive organ in bryophytes.
Amphithecium: A cell layer in the developing moss embryo that forms the capsule wall.
Step 3: Final Answer:
The pseudopodium is the gametophytic structure that elevates the sporogonium in *Sphagnum*.