Overview of the Plant Kingdom
The plant kingdom is categorized into five main groups:
- Algae: Simple, thalloid, autotrophic organisms that predominantly live in water. They are classified into three groups—Chlorophyceae, Phaeophyceae, and Rhodophyceae—based on their pigments and types of stored food. Reproduction can be vegetative, asexual via spores, or sexual through gamete formation, displaying forms such as isogamy, anisogamy, and oogamy.
-
Bryophytes: These are more complex than algae, living in soil but relying on water for sexual reproduction. They possess thallus-like structures attached to substrates by rhizoids and are divided into liverworts and mosses. The gametophyte is the main plant body, producing gametes in antheridia and archegonia, leading to zygote formation and sporophyte development.
-
Pteridophytes: Here, the sporophyte is the dominant phase, featuring true roots, stems, and leaves with well-differentiated vascular tissues. They reproduce via spores forming gametophytes, which need damp environments for growth.
-
Gymnosperms: Known as naked-seeded plants, gymnosperms have ovules that are not enclosed by an ovary wall. Their reproductive structures consist of male and female cones where microspores and megaspores are produced.
-
Angiosperms: The most advanced group, angiosperms are further divided into dicotyledons and monocotyledons, distinguished by seed structure and vascular formation.