CSS Paper Botany 2010 MCQs

Polytrichum is the genus name for the hair-cap mosses. It belongs to the family Polytrichaceae, which is placed within the order Polytricales and the class Bryopsida, distinguishing it from other moss groups.

Funaria is a well-known genus of mosses. In the classification of bryophytes, mosses are placed under the class Bryopsida. While Bryophyta is the division, Funariales is the order, and Funariaceae is the family. Therefore, Bryopsida is the correct taxonomic class for this organism, representing the true mosses characterized by their distinct gametophyte and sporophyte generations.

During the development of the Funaria capsule, the amphithecium undergoes periclinal divisions. In the mature state of the capsule wall, the amphithecium is typically organized into eight layers of cells, which provide structural support and protection for the internal spore-producing tissues.

Hydroids are specialized water-conducting cells found in the central strand of the Funaria stem. At maturity, these cells lose their protoplasm, becoming empty and dead, which allows them to function effectively in the conduction of water and minerals.

Like all bryophytes, Polytrichum exhibits an alternation of generations where the gametophyte is the dominant, independent, and photosynthetic phase. The sporophyte remains physically attached to and nutritionally dependent on the gametophyte throughout its life.

In the anatomical structure of the moss capsule, the region above the theca, often associated with the operculum or the upper capsule wall, is characterized by a specific number of epidermal cell layers. Research into the developmental morphology of these mosses indicates that this region typically consists of 4 to 5 layers of epidermal cells, providing structural integrity to the upper portion of the sporangium.

Paraphyses are sterile, hair-like structures interspersed among the sex organs in Funaria. They serve to protect the developing gametangia and assist in water retention. In Funaria, these filaments are typically composed of 4 to 6 cells in height.

The rhizome of Polytrichum is a subterranean structure that typically bears reduced, scale-like leaves. These leaves are often devoid of chlorophyll, appearing colorless or pale, and frequently turn brown as they mature or become necrotic. Therefore, both colorless and brown appearances are characteristic of these specialized leaf structures found on the rhizome.

The annulus is a specialized ring of cells located at the junction between the operculum and the theca of the moss capsule. As the capsule matures and dries, the annulus cells undergo degeneration or hygroscopic changes, which creates mechanical tension. This process facilitates the dropping off of the operculum, allowing for the eventual release of spores.

Funaria hygrometrica is the most well-known and cosmopolitan species of the genus Funaria. It is frequently found in diverse habitats, including burnt soil, which is why it is sometimes called the 'cord moss' or 'bonfire moss'. Its wide distribution and ease of cultivation make it a model organism for studying bryophyte biology, development, and the physiological responses of mosses to environmental conditions.