Introduction

Along with animals, there are also various species of plants living and surviving in this world. They are also different from one another. Some are big some are small, some are flowering plants some are non- flowering plants, some prepare food and some does not prepare food, some are unicellular some are multicellular and so on. They differ in their size, shape, structure, habit, habitat, mode of life etc. Some of the examples of plants are the fern, mustard, sunflower, mango, grass, spirogyra etc. Plants are very important for us. It provides food, shelter, clothes, medicines, prevents soil erosion, balance ecosystem, and many other important things. Some of the general characteristics of plants are discussed below,

General characteristics of plants

• Their body is differentiated into root, stem, and leaves.
• Most of the green plant prepare their own food by photosynthesis.
• Most of the plants contain green pigments called chlorophyll.
• They grow throughout the life.
• Plants cannot move from one place to another like animals, they are fixed in the soil by roots.

Classification of Plants

There are various species of plants. Some are microscopic and some are big. Some plants bear flowers and some do not bear a flower. Plants are classified into different groups so that we can study easily and avoid confusion. Plants are classified into two sub- kingdoms on the basis of flowering and non- flowering features. They are described below,

Cryptogams

Cryptogams are also called flowerless or seedless plants as they do not bear flower and seeds. They are also called 'lower plants' that reproduce through spores. They do not have the structure of plants like true stems, roots, leaves, flowers, or seeds etc. Some of the general characteristics of cryptogams are discussed below,

• They do not bear flowers and seeds.
• They reproduce through spores.
• They need a moist environment to survive.
• They may be aquatic or terrestrial.
• They are the simplest and primitive plants.
• Some of the examples of cryptogams are yeast, Chlamydomonas, nostoc, ulothrix, spirogyra, ferns etc.

Cryptogams are further divided into three divisions. They are given below,

Thallophyta:Thallophyta includes those plants whose body is not differentiated into roots, stem and leaves. The plant body is called thallus as it is formed by an undifferentiated mass of cells. They may or may not contain chlorophyll. They may be unicellular or multicellular. The division thallophyta is again sub- divided into the following groups,

Algae

The general characteristics of algae are discussed below,

• They are mostly found in water or moist place or well-lighted area.
• They may be unicellular or multicellular.
• They contain chlorophyll.
• Their cell wall is made up of cellulose.
• They are autotrophs as they can prepare their own food by photosynthesis.
• Examples: volvox, ulothrix, spirogyra etc.

Fungi

The general characteristics of fungi are discussed below,

• Most of the fungi plants are multicellular except yeast.
• The grow in moist and dark places.
• They lack chlorophyll.
• They store food in the form of glycogen.
• They are known as heterotrophs as they cannot prepare their own food.
• Cell wall is made up of fungus cellulose or chitin
• Examples: mushroom, mucor, yeast etc

Bryophyta: It includes plants like mosses, liverworts, hornworts etc. Some of the general characteristics of bryophyta are discussed below,

• They are found in moist, cool and shady places.
• They are known as amphibian plants as they need water for reproduction.
• They contain chlorophyll and can prepare their own food.
• The plant body is leaf- like thallus except moss.
• They are multicellular.
• Examples: liverwort, moss, hornwort, riccia etc.

Pteridophyta: Pteridophyta is also known as 'wing- plants'. They are seedless plants. Some of the general characteristics of pteridophyta are discussed below,

• The plant body is differentiated into root, stem, and leaves.
• They are called autotrophs as they can prepare their own food.
• They grow in moist and shady places.
• They have feathers like leaves.
• They are the most developed non- flowering plants.
• They are multicellular.
• Examples: fern, azola, marsilea, lycopodium, horsetail, etc.

Phanerogams

This group includes the most developed and advanced plant. They can prepare their own food. They bear flowers and seeds. Flowers are one of the most important parts of plants as they make plants more attractive. They produce flowers of different structure and colours. They have well developed the reproductive system. The flower acts as a reproductive part as it produces fruits and seeds. They have well-developed root and shoot systems. Phanerogams have only one division called spermatophyta which is further divided into two sub- divisions called gymnosperms and angiosperms.

Gymnosperms

They are naked- seeded plant as their seeds are not enclosed in a fruit. They are mostly found in hills. They were the first plant to have seeds. Some of the general characteristics of gymnosperms are discussed below,

• They do not produce flowers and fruits instead they produce cone.
• Their seeds are not covered. They have naked seeds.
• They are woody trees and live for many years.
• The plant body is differentiated into root, stem, and leaves.
• They have needle- shaped green leaves.
• Examples: pine, cycas, fir, deodar, etc

Angiosperms

Angiosperms are the largest group among all the groups of plants. About 80% of the green plants belongs to the group angiosperms. It includes very important plant that acts as a source of food, shelter, and clothing for humans. They grow in all types of habitats. Some of the general characteristics of angiosperms are discussed below,

• They are autotrophs as they can prepare their own food.
• Their seeds are covered or enclosed inside the fruits.
• The plants of this groups grow in a different habitat like some may be hydrophytes, some mesophytes, xerophytes, and epiphytes.
• The plants of this group may be herbs, shrubs or trees.
• Examples: pea, mustard, wheat, bamboo etc.

The angiosperms are further divided into two classes, monocotyledons, and dicotyledons.

Monocotyledons: Monocotyledons are those plants that have only one cotyledon. Some of the characteristics of monocotyledons are discussed below,

• The plants have fibrous root.
• They have only one cotyledon or seed leaf in their seeds.
• Their leaves are long and narrow and contain parallel venation.
• They have a weak stem.
• Examples: wheat, barley, bamboo etc.

Dicotyledons: Dicotyledons are those plants that have two cotyledons in their seeds. Some of the general characteristics of dicotyledon plants are discussed below,

• Their leaves are broad and contain reticulate venation.
• The plants have a tap root.
• They have two cotyledons or seed leaves in their seeds.
• They have a strong stem.
• Examples: pea, mustard, orange, mango etc.