Question

Mesarch xylem occurs in
A. Monocots
B. Dicots
C. Ferns
D. Bryophytes

Answer 1

Hint: 'Mesarch' term is used when there is more than one strand of primary xylem in a stem or root. Also, this xylem develops from the middle of a strand in both directions. Thus, the metaxylem is present on both sides of the strand with the protoxylem between the metaxylem- the peripheral and central. The leaves and stems of ferns show mesarch development.

Complete answer:
Option A- Monocots
Monocotyledons or monocots are grass or grass-like flowering plants (angiosperms). The seeds of these typically contain only one embryonic leaf or cotyledon.

Option B- Dicots
The dicots also known as dicotyledons are one of the two groups of flowering plants or angiosperms that were formerly divided. The characteristics of this group are that the seed has two embryonic leaves or cotyledons.

Option C- Ferns
A fern is a member of a group of vascular plants. They reproduce via spores and do not seed or flower. They are different from mosses by being vascular, i.e., they have specialized tissues that conduct water and nutrients. Also, in their life cycles, the sporophyte is the dominant phase.

Option D- Bryophytes
Bryophytes consist of three divisions of non-vascular land plants (embryophytes):
liverworts
hornworts
mosses.

Thus, option C- Ferns, is the correct answer.

Note: There are several vascular strands in research development and in each of these, the protoxylem is located in the center surrounded by the metaxylem. This type of primary xylem development is seen in many species of ferns (Gifford and Foster 1989).