Question

A leafy gametophyte plant with multicellular rhizoids and sporophyte differentiated in foot, seta and capsule should belong to
A. Psilopsida
B. Hepaticopsida
C. Bryopsida
D. Lycopsida

Answer 1

Hint: Bryophytes have a dominant and haploid gametophyte which is a leafy or thalloid structure. These plants lack true leaves, stem, and roots. However, some gametophytes of some bryophytes develop the structures similar to the leaves and roots.

Complete answer:
Pteridophytes are the vascular plants and have dominant sporophyte which is differentiated into true roots, stem, and leaves. Lycopsida (club mosses) and psilopsida are the classes classified under pteridophytes.

Bryophytes are the small leafy or flat plants that are mostly found in moist places. The liverworts (hepaticopsida), mosses (bryopsida), and hornworts (anthocerotopsida) are classified as bryophytes. The gametophyte of liverworts is mostly a flat and lobed structure called a thallus. It bears unicellular rhizoids.

Mosses have leafy gametophytes. The leafy gametophyte of mosses has a variable number of rows of leaves on the upright axes. The gametophyte is anchored to the substratum through rhizoids. Mosses have multicellular and branched rhizoids. The gametophyte bears sex organs called antheridia and archegonia at the apex of the shoots. Sexual reproduction includes the fusion of gametes to form a zygote which in turn develops into the sporophyte.

Sporophyte in mosses is composed of the foot, seta, and capsule. The spores are produced in the capsule and germinate to form the leafy gametophyte. The foot anchors the sporophyte to the gametophyte while seta serves as a stalk.

Hence, the correct answer is option (C).

Note: Sporophyte of mosses is attached to the gametophyte and is nutritionally dependent on it. However, the young sporophyte of mosses is green and photosynthetic. The capsule of some mosses is covered with calyptra. Polytrichum, Sphagnum, and Physcomitrella are some examples of mosses.