Kingdom Plantae

Kingdom Plantae refers to any eukaryotic chlorophyll-containing organism that is typically referred to as a plant. Plant cells are eukaryotic in nature, with significant chloroplasts and a cellulose-based cell wall. Algae, bryophytes, Pteridophytes, gymnosperms, and angiosperms are all members of the Plantae family. A few members, such as insectivorous plants and parasites, are partially heterotrophic.

Insectivorous plants include bladderwort and Venus flytrap, while Cuscutaexists like a parasite.

Plants have two unique phases in their life cycle: diploid sporophytic and haploid gametophytic, which alternate. The lengths of the haploid and diploid phases, as well as whether they are free-living or dependent on others, varied between plant families. Alternation of generation is the term for this phenomenon.

Plants are classified according to the following criteria:

1. Plant body: Whether or not a well-differentiated plant body exists. Root, stem, and leaves, for example.

2. Vascular system: The presence or absence of a vascular system for water and other material movements. Phloem and Xylem, are two types of vascular tissues in plants.

3. The presence or absence of flowers and seeds, as well as whether the seeds are bare or wrapped in fruit, are all factors in seed production.

According to the above-mentioned criteria, the plant kingdom has been divided into five subgroups:

(A) Thallophyta:

Thallophytes have a thallus-like body structure and lack a well-differentiated body structure. Plants having a primitive and simple body structure are included. The thallus is the plant's main body, and it can be filamentous, colonial, branching, or unbranched. Algae such as green algae, red algae, and brown algae are examples. Volvox, Fucus, Spirogyra, Chara, Polysiphonia, Ulothrix, and other species are common examples.

Figure 13 Thallophytes

(B) Bryophytes

Bryophytes are plants that lack vascular tissues. Root-like, stem-like, and leaf-like components make up the plant's body. Bryophytes are terrestrial plants that are also known as "plant amphibians" since they require water for sexual reproduction. They thrive in wet, shaded environments. Mosses, hornworts, and liverworts are all members of the Bryophyta family. Marchantia, Funaria, Sphagnum, Antheoceros, etc. are well-known examples.

Figure 14 Bryophyta

(C) Pteridophyta:

Pteridophytes have a plant body that is well-differentiated into roots, stems, and leaves. They have a circulatory system that allows water and other chemicals to be transported. Selaginella, Equisetum, Pteris, and other common examples are only a few.

Non-flowering and non-seed bearing plants. E.g. Thallophyta, Bryophyta, Pteridophyta are collectively known as Cryptogams.

Figure 15 Pteridophyta

(D) Gymnosperms:

Gymnosperms have a plant body and vascular tissues that are well-differentiated. They produce naked seeds, which are seeds that are not encased in a fruit. Gymnosperms include plants such as Cycas, Pinus, Ephedra, and others.

Figure 16 Gymnosperms

(E) Angiosperms:

Seed-bearing vascular plants with a well-differentiated plant body are known as angiosperms. Angiosperm seeds are contained within the fruits. Angiosperms are found all over the world and range in size from 0.1 cm to 100 m. For example, Wolffia is a little plant that grows to be around 0.1 cm tall, while Eucalyptus trees grow to be over 100 m tall. According to the number of cotyledons contained in the seeds, angiosperms are further split into monocotyledons and dicotyledons. Mango, rose, tomato, onion, wheat, maize, and other common examples are only a few.

Flowering and seed-bearing plants. E.g. Gymnosperms, Angiosperms are known as Phanerogams.

Figure 17 An angiosperm