Question

The Rhynia belongs to which one of the following
a. Silurian
b. Devonian
c. Carboniferous
d. Permian

Answer 1

The plants that possess vascular tissues such as xylem and phloem are called vascular plants. These plants include all seed-bearing plants that are gymnosperms as well as angiosperms and pteridophytes. The pteridophytes include ferns, lycophytes, and horsetails. The body of vascular plants is well-differentiated into roots, stems, and leaves. The sporophytic phase is dominant in vascular plants.

Complete answer:
Rhynia is described as a single-species of Devonian vascular plants. It has a creeping rhizome that contains a repeated dichotomous and adventitious branching. These are present upright and pass upwards into the aerial axes. The axes of rhizomes are cylindrical and naked. They lack stomata and possess a similar morphology and internal anatomy to the aerial axes.

Rhynia is the most common form, which is about 18 cm tall and has water-conducting cells in its stem. These water-conducting cells are tracheids.
The underground runners of Rhynia are connected to its above ground stems. These stems are photosynthetic and branched evenly.
The Rhynia is a Devonian plant because it had more advanced anatomical features than bryophytes.

Hence, the correct answer is option (B).

Note: The vascular plants differ from nonvascular plants. The vascular plants have special tissues such as xylem and phloem. These tissues transport water, minerals, and food through every part of the plant. On the contrary, non-vascular plants do not have these special tissues. So, in these plants, the substances travel from one cell to the next cell. The gametophytic phase is dominant in nonvascular plants.