Question

Which one of the following is the first group of vascular plants?
a. Thallophyta
b. Bryophyta
c. Pteridophyta
d. Spermatophyta

Answer 1

Hint: Vascular plants are also called as Tracheophytes, but newly formed or first formed vascular plants do not have mature vascular tissue, so this is called as eutracheophytes, one of the examples for this is rhyniophytes.

Complete answer:
- The vascular plants on the earth began almost 420 million years ago.
- The first group of vascular plants that are evolved is Pteridophytes, and these plants are also called cryptograms because these plants do not produce either flowers or seeds.
- Some of the examples of the pteridophytes are ferns, horsetails, etc.
- Vascular plants are the plants that have vascular tissues that are helping to conduct different things, such as xylem and phloem, where xylem is helpful for the conduction of water and minerals, while the Phloem is helpful for conduction of food substances. But in first formed vascular plants, even though these tissues are present, they are not that much well defined, as they have lignified walls vascular tissues.
- The lifecycle of the first formed vascular plants that are pteridophytes has 2 phases, which means they have, free-living gametophyte stage which is alternated by the sporophyte stage and both of these phases are independent of each other.
The body of the sporophyte is well-differentiated into root, stem, and leaves, and in these plants, roots are always adventitious and stem are underground.

Hence, the correct answer is option (C).

Note: The reproduction of these plants occurs in an alternate manner, this is the plant has sporophytes phase where spores are produced by the mitosis, and it also has a gametophyte phase where the gametes are produced by meiosis. And the spores which are produced may be homosporous or heterosporous.