Chapter 22, Problem 1RQ

Summary Introduction

To write:

Define gymnosperm and distinguishable features from other major groups of plants.

Introduction:

Gymnosperm constitutes one of the two major subdivisions of the Spermatophyta division. The subdivision Gymnospermae includes autophytic evergreen trees and shrubs, which are exceptionally enchanting due to their attractive shapes and exquisite habit. Gymnosperms, as the name suggests, include plants with naked seeds unlike angiosperms with enclosed seeds.

Explanation of Solution

Gymnosperms are plants having seeds exposed on the megasporophylls (carpels of the ovary) at the time of their development. The systematic position of Gymnospermae subdivision lies between Pteridophyta and Angiospermae because gymnosperms have close resemblances with the pteridophytes on one hand and angiosperms on the other.

Like angiosperms, gymnosperms are not advanced plants due to the presence of certain distinctive characters. Gymnosperm is distinguished from other major plant groups by the fact that they contain naked seeds, so there is no formation of fruit, unlike in angiosperms where seeds are enclosed in the ovary. The presence of dimorphic leaves (green foliage leaves and brown scale leaves) and simple unisexual flowers are considered as distinguishable features in respect to other plants.

Conclusion

Hence, gymnosperms are seed plants that lack advanced and specialized characters like angiosperms. During pollination, the ovules are freely exposed to carpels; thus, seeds remain naked or not enclosed in a mature ovary (fruit chamber). This character distinguished gymnosperms from other major groups of plants.