Biological Classification

Kingdom Plantae

You see a variety of plants around you. You can see they have different leaves, stems, and fruits. Why does that happen? Wouldn’t it be very boring if all the plants were alike? Who can eat only apples all through their life!! Never! So, we will study the diverse kingdom of Plantae here.

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Kingdom Plantae

Kingdom Plantae includes green, brown and red algae, liverworts, mosses, ferns and seed plants with or without flowers. They have the following characteristics:

  • They are multicellular organisms with walled and frequently vacuolate eukaryotic cells.
  • These contain photosynthetic pigment in plastids. The principle mode of nutrition is photosynthesis.
  • They are primarily non-motile and live anchored to a substrate.
  • Reproduction is primarily asexual or sexual. The reproductive organs are multicellular. They form a multicellular embryo during development from the zygote. Algae lack the embryo stage.
  • The life cycle consists of alternating haploid gametophyte and diploid sporophyte generation. This phenomenon is called the alternation of generation.                     Plantae

Thallophyta (Algae)

They are simple, autotrophic non-vascular plants. They have unicelled sex organs and no embryo formation. These grow in specialized habitats:

  • Cryophytes: These grow on snow or ice.
  • Thermophytes: These grow in hot water.
  • Epiphytes: These are those algae that grow on other plants (algae, angiosperms). Examples include Oedogonium, Cladophora, Vaucheria, etc.
  • Endophytes: Some blue-green algae grow as endophytes inside other plants e.g., Anabaena growing inside the leaf of Azolla (fern).
  • Parasites: The alga Cephaleuros virescens grows a parasite on the tea leaves.

Browse more Topics under Biological Classification

Know more about Kingdom Animalia


Bryophyta (Gk: Bryon = moss; phyton = plants) is the grouping that consists of the simplest and primitive land plants. We also regard these as ‘the amphibians of the plant kingdom’. Bryophytes are most common in moist and shady places. Some bryophytes also grow in diverse habitats like extremely dry or watery habitats. They reproduce sexually. Antheridium is the male sex organ. On the other hand, archegonium is the female sex organ.


The pteridophytes (Gk. Pteron = feather and phyton = plants) refers to all those plants with feathers like fronds of ferns. They do not have flowers or seeds. These plants are mostly terrestrial. They prefer shady habitats. They have a Sporophytic plant body. The pteridophyte usually has a single apical cell with three cutting faces in the shoot apex. Let us now look at the sub-phyla of this group.

  • Sub-phylum: Psilopsida: These are the oldest known vascular plants; most of them (except Psilotum and Tmesipteris) are fossils. The body of the plant is relatively less differentiated. Roots are absent in these plants. Instead, you can find a dichotomously branched rhizome.
  • Sub-Phylum: Lycopsida: The plant body is differentiated into root, stem, and leaves. Leaves are usually small (i.e., microphyllous) with a single unbranched vein. Sporangia develop in the axil of the sporophylls.
  • Sub-Phylum: Sphenopsida: The stem is differentiated into nodes and internodes. The leaves are microphyllous. You can find them in whorls at each of the nodes.
  • Sub-Phylum: Pteropsida: The plant body is well-differentiated into root, stem, and leaves. The leaves are megaphyllous, pinnately compound.

You know about Kingdom Fungi


The angiosperms, or flowering plants, are the most dominant and ubiquitous vascular plants of present-day flora. These plants are primarily responsible for changing the green and yellow melancholy of the earth’s vegetation. They do so by their beautiful and colorful brightness and fragrance of their flower.

The term angiosperm means ‘enclosed seed’. This is so because the ovules or potential seeds are enclosed within a hollow ovary. We can divide the plants of Angiosperms into two major groups as – Dicotyledons and Monocotyledons.


They show the following distinguishing characteristics:

  • We see taproots in the members of this group.
  • The leaves in members of these classes exhibit reticulate (net-like) venation.
  • The flowers are tetramerous or pentamerous having four or five members in the various floral whorls, respectively.
  • The vascular bundles arranged in a ring, number 2–6, open and with cambium.
  • The seeds of dicotyledons are with two cotyledons as the name indicates.


They show the following distinguishing characteristics:

  • We see adventitious roots in the members of this group.
  • The leaves are simple with parallel venation.
  • The flowers are trimerous. They have three members in each floral whorl.
  • The vascular bundles scattered in the ground tissue, many in number, closed and without cambium.
  • The seeds of monocotyledons are with one cotyledon as the name indicates. e.g., Cereals, bamboos, sugarcane, palms, banana, lilies and orchids.

You can download Biological Classification Cheat Sheet by clicking on the download button below

Kingdom Plantae

Solved Example For You

Question: Write a short note on gymnosperms from Kingdom Plantae.

Answer: Living gymnosperms are mostly perennials, xerophytic, evergreen, arboreal and woody plants. We can find them growing as wood trees, bushy shrubs or rarely as climbers (e.g., Gnetales). They are never herbs or annuals. The external features of these are:

  • The plant body is sporophyte and differentiated into root, stem, and leaves.
  • The plant possesses a well-developed tap root system. In some cases, the roots are symbiotically associated with algae (e.g., Coralloid roots of Cycas) or with fungi (e.g., Mycorrhizal roots of Pinus).
  • The stem is erect, aerial, solid, woody and branched (unbranched in Cycadales) but almost tuberous in Zamia. The leaves may be microphyllous or megaphyllous.

FAQ’s for You

Q1. Give the outline for kingdom plantae.

Answer: Kingdom Plantae is classified into the following groups:
Thallophyta: Algae belong to this group. They have chlorophyll. They are phototrophic. They are mostly aquatic. Other members include fungi.
Bryophyta: They are found in cool, damp areas. They have thallus like plant body attached to the substratum. They do not have true roots, leaves and stems. An example includes lichens.
Pteridophyta: They are found in cool, damp and shady places. They have differentiated and well-developed roots stem and leaves. They bear sporangia which produce spores. An example includes ferns.
Gymnosperms: They have naked seeds. The examples include pinus, They do not have ovary wall. banyan tree.
Angiosperms: The seeds are enclosed by the fruits. The examples include flowering plants.

Q2. In the given word ‘Kingdom Plantae’, identify the category and taxon.
A. Kingdom Plantae refers to taxon
B. Kingdom Plantae refers to taxon and plants refer to category
C. Kingdom Plantae refers to taxon and plants refer to taxon
D. Plants refer to category

Answer: Kingdom Plantae refers to a category in the taxonomic hierarchy of classification. Plants refer to a taxon. There are different types of plant species, which are found on planet earth. They are sorted and classified into a separate kingdom known as Kingdom Plantae. This classification is based on their similarities and differences.
The Kingdom Plantae is also called as kingdom Metaphyta. The Kingdom Plantae includes all types of eukaryotic, multicellular, photosynthetic plants found in this biosphere.

Q3. Kingdom plantae shows two phases of life, gametophytic and
A. Autotrophic
B. Sporophytic
C. Saprophytic
D. Geophytic

Answer: Bryophytes are the plants in which the life cycle has two phases gametophytic and sporophytic, alternating to each other. This phenomenon is called alternation of generation. Gametophytic phase is haploid, autotrophic, gametes(male and female) formative and responsible for the sexual reproduction. Sporophytic phase is the subsidiary phase which is diploid, heterotrophic and spore formative and responsible for the asexual reproduction. For example, Riccia, Funaria.
So, the correct answer is option B.

Q4. Give an outline of classification of the kingdom plantae with one example of each.

Answer: The kingdom plantae is divided into five divisions. They are
Algae. Plants belonging to this group lack a well defined body structure. E.g.: Spirogyra.
Bryophyta: Plant body differentiated into stem and root, but plants lack a vascular system. E.g.: Merchantia.
Pteridophyta: Plant body is differentiated into stem, roots and leaves and they have a vascular system. They do not bear seeds. E.g.: Ferns.
Gymnosperms: They have a well differentiated plant body and vascular system and plants bear seeds (seeds however are naked). E.g.: Pine.
Angiosperms: Plant body well differentiated and plants bear seeds (seeds enclosed in fruits). E.g.: Mango.

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2 responses to “Introduction to Biological Classification”

  1. Danladi Solomon says:

    What is an example of liverwort

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