Classification of plant Kingdom

Classification of plant


The study of different types of trees & plants is called Botany.
Theophrastus is called the father of Botany.

1. Classification of plantae 

In the years 1883, Eichler has classified the Botanical world as under:

I. Crytogamous plants ( non_ flowering plant)

There are two flower and seed in these types of plants. These are classified into the following groups.


1. This is the largest groups of the plant Kingdom. 

2. The body of plants of this group is thalus like i .e., plant are not differentiated into roots, stem and leaves.

3. It is the lower most group of plant Kingdom. 

4. There is no conducting tissue. It is divided into two groups .
(a) Algae and (b) Fungi.

(a) Algae

1. The study of algae is called phucology.

2. The algae normally have chlorophyll and autotrophic mode of nutrition. 

3. Its body is thalus like. It may be unicellular, colonial or filamentous. 

4. Classification of the group algae is based on nature of pigment.

Useful Algae:

1. As a food: porphyra, Ulva, Surgassum, Laeminar, Nostoc etc.

2. In making lodine: Laeminaria, Fucus, Echlonia etc.

3 . As a manure: Nostoc, Anabana, kelp etc.

4. In making medicines: Chloreloline from Chlorella and Tincher iodine is made from Laminaria.

5. In research works:  Chlorella, Acetabularia, Belonia etc.

☆ Spirogyra is commonly known as ' pond Silk'.

Note : An astronaut can get protein food, water and oxygen by sowing the chlorella algae in the tank of the aircraft so chlorella is known as space algae.

☆ Agar is prepared from algae like Gelidium and Graciliaria. It is used to grow microbes and in preparation of icecream and jelly.

(b) Fungi

1. Study of fungi is called Mycology. Organism of his group may be unicellular or multicellular. 

2. Fungi is without chlorophyll,  central carrier tissue less, Thalophyta.

3. Accumulated food in fungi remains as Glycogen

4. Its cell wa is made up of chitin. Ex. Albugo, Phytophthora, Mucor, Yeast etc.

Fungi may creates serious diseases in plants.Most of the damage is caused by rust and smut. Main Fungal diseases in plants are as__ 

White rust of cruciferous, Loose smut of wheat, Rust of wheat, early Blight of potato, Red rot of sugarcane, Tikka diseases of groundnut, Wart disease of potato, Vrown leaf spot of rice, Late blight of potato, Damping off of seedlings etc.

● Rhizopus is a fungi commonly known as ' bread mould'. 

● Heterothallism in fungi was discovered by AF Blakelee 

● Alfa _ toxins are produced by fungi.

● Lichens are the association of algae and fungi.

● Lichens developing on rocky substrates are called saxicolous.

● Lixchens are the first organism which colonies on bare rock.

● Yeast is unicellular fungi reproduce through budding.

● The sexual reproductive organ of Aspergillus are antheridium and ascogonium.


This is the first group of land plants. In this division approximately 25,000 species are included.

1. In bryophtyta there is lack of xylem and phloem tissues. 

2. Plant body may be of phallus like and leafy erect structure as in moss.

3. They lack true roots, stem and leaves.

4. This community is also called Amphibian category of the plant Kingdom. 

● Water conduction takes place in mosses through parenchyma .

The most namely Sphagnum is capable of soaking water 18 times of it's own weight .Therefore,  gardeners use it to protect from drying while taking the plants from one place to another. 

● The Sphagnum miss is used as fuel.

● The Sphagnum moss is also used as antiseptic. 


The plants of this group is mostly found in wet shady places, forests and mountains. 

1. The body of plants is differentiated into roots stem and leaves. Stem remains as normal rhizome.

2. Reproduction occur by spores produced inside the sporangia.

● Sporangia bearing leaf of a ferns is called ' Sorus'. 

3. Gametophyte phase is short lived.The diploid zygote develops into an embryo.

● Gametophyte is called prothallus in pteridophytes.

4. Plants of this community have conducting tissues. But xylem does not contain vessels a d phloem does not contain companion cells.

Examples: Ferns, Azolla, Pteridium, Lycopodium etc.

● In the neck cell of archegonium  of ferns one binucleated cell is present. 

● Mosses ( Bryophytes) and ferns ( Pteridophytes) are called amphibian of plant Kingdom.

● Marsileo, Fern and Horse tail are example of pteridophyta.

● Fern and Fern allies belong to the Kingdom pteridophyta.

II. Phanerogamous ( Flowering plant)

Plants of this group is well developed. All the plant in this group bear flower, fruit and seed. Plants of this group can be classified into two sub_ groups _ Gymnosperms and Angiosperm.

(A) Gymnosperm( Naked Seed)

1. These plants are in the forms of trees and bushes. Plant body are differentiated into root, stem & leaves.

2. Plants are woody, perennial and tall. Plant bear naked seed.

3. Its tap roots are well developed. 

4. Pollination takes place through air.

The longest plant of the Plant kingdom, Sequoia gigantia comes under it. Its height is 120 meters. This is also called Red Wood Of California

● The smallest plant is Zaimia Pygmia.

● Living fossils of plant are Cycas, Ginkgo biloba and Metasequoia.

● Ovule and Antherozoids of Cycas is largest in plant Kingdom. 

● Cololloid root of Cycas help in absorption of water and fixation of nitrogen. 

● The pollen grains of Pinus are so much in number that later it turns into Sulphur showers.

Importance of Gymnosperm

1. As a food_ Sago is made by extracting the juice from the stems of Cycas. Therefore, Cycas is called Sago__ palm.

2. Wood __  The wood of Pine, Sequoia, Deodar, Spruce etc. is used for making furniture. 

3. Vapour oil__ We get Tarpin oil from the trees of Pins, Cedrus oil from Deodar tree and Cedcast oil from Juniperous wood.

4. Tannin__   It is useful in tanning and making ink.

5 Resin __  Resin is extracted from some conical plants which are used in making varnish, polish, paint etc.

● Resin is the product of coniferous tree.

● Best example of polyembryony is citrus.

(B) Angiosperm ( Covered Seed)

1. In the plants of this sub__ group seeds are found inside the fruits. ( Concealed Seeds) 

2. In these plants root leaves,  flowers, fruits and seeds are fully developed. 

Plants of this sub_ group have seed__ coat in seeds. On the basis of number of cotyledons plants are divided into two categories __ 1. Monocotyledon and 2. Dicotyledon.

Monocotyledon plants: Those plants which have only one cotyledon in seed. Example:

Dicotyledon plants: Those plants which have two cotyledon in its seed are called dicotyledon.  Example:

● Leaves are the lung of plant.

● Plant from which coca and chocolate are obtained is a shurb

● Banana is a shurb.

● Trochodendron is a vessels Angiosperm.

● Pulses are obtained from the family Leguminacae.

● From the bark of cinchona a drug quinine is obtained used in malaria fever.

● Chloroplasts found in sugarcane plant shows dimorphism.

● The maximum fixation of solar energy is done by green plant.

● Golden rice contain Beta _ carotene gene which comes from carrote. It is a variety of rich produced by genetic engineering to biosynthesis of Beta__ carotene,  a precursor of vitamin A.

● Potato, Tomato and Bronjal are three different species but all belong to genus Solonum.


● Study of virus is called virology. 

● Virus was discovered by Russian scientist Ivanovsky in the year 1892.( During the tests of Mosaic disease in tobacco).

● In nature, there are ultra microscopic particle known as viruses. 

● It has both the characters of living and non living, so it is a connecting link between living & non living. 

● Dr. Stranley first isolated the virus causing Mosaic disease in tobacco in the form of crystals. 

Characters of virus

1. They became active inside a living cells or host cell.

2 . Nucleic acids replicate themselves and they reproduce rapidly. 

3. They cause disease like bacteria & fungi.

According to parasitic nature, virus is of three types__ 

1. Plant virus _  RNA is present as nucleic acid in 75% plant virus.
2. Animal virus__  DNA or sometimes RNA is found in it.

3. Bacteriophage__  A virus that infects and replicates within bacteria.They kill the bacteria. Example _ T_ 2 phage. Bacteriophages are composed of nucleic acid molecule surrounded by a protein sheath.

● In man virus cause disease like mumps, chicken pox, hepatitis, polio, AIDs, Herpes etc.
● HIV often change its structure due to the presence of an enzyme reverse transcriptase.

● The enzyme integrates produced by virus allow the integration of HIV _ DNA into the host cell DNA .

● EBOLA is a virus, causes Ebola fever. Fruit Bats are the natural host of this virus, first outbreak in West Africa. 

Note: Those viruses in which RNA is found as genetic material are called Retrovirus.

● Viruses are parasite which need living cell to reproduce. Outside host it is smilar to chemical substance.

● Virus have no enzyme of their own.


It was discovered by Anthony Von Leeuwenhook of Holland in the year 1683.

● Leeuwenhook is called the father of Bacteriology.  In the year 1829  Ehrenberge called it bacteria.

● The year 1843_ 1892 _ Robert Koch discovered the bacteria of Tuberculosis diseases. 

● The year 1812 _ 1892 _ 1892 _ Louis Pasteur discovered the vaccine of Rabies and pasteurization of milk.

On the basis of shape, bacteria are of different types:

1. Bacillus:  This is rod_ like or cylindrical. 

2. Round or Cocus: These are round and the smallest bacteria. 
3. Comma shaped or Vibrio: Like the English sign (,) example _ Vibrio cholerae etc.

4. Spirillum: Spring or screw shaped.

● Some species of Azotobacter, Azospirillum and Clostridium bacteria live freely in the soil and fix atmospheric nitrogen into the nitrogenous compound. 

● The Bacteria capable of converting nitrite to nitrate is nitrosamones.

Anabaena and Nostoc cynobacteria fix atmospheric nitrogen into soil.

● The species of Rhizobium, Bradyrhizobium etc. live in the roots of the Leguminous plants capable of converting atmospheric nitrogen into its compound .
Example  __ Peas, Pegion Peas, Gram etc.

● Rhizobium are called symbiotic bacteria. 

● The harmful substances produced by the microbes are known as Toxins.

Note : To preserve the milk for many days pasteurization is done. There are two methods of pasteurization __ 

(a) Low temperature holding method ( LTH) Milk is boiled at 62.8 degree Celsius for 30 minutes. 

(b) High temperatures short time method ( HTSt) :  Milk is boiled at 71.7 degree Celsius for 15 seconds.

● In leather industry separation of hair and fat from leather is done by bacteria. This is called tanning of leather. 

●  Pickles, syrup is kept in salt or in dense liquid of sugar so that in case of bacterial attack bacteria are plasmolysed and destroyed. Therefore, pickles do not get spoiled soon and can be preserved for long time.

● The citus, fruit and pickles are not stored in iron container because it contain organic acid.

● In the cold storage objects are kept at low temperature ( _10 degree celsius to _ 18 degree celsius).

● Mycoplasma: Smallest known prokaryotic cell causing pleuropneumonia. It is also known as PPLO.

● Waksman got the Nobel prize for the discovery of antibiotic streptomycin. 

● Alexender Fleming discovered first antibiotic.          Penicillin 

● Xenobiotics are inherently resistant to microbial attack are called recalcitrant.

● Microbial type culture collection centre is situated at Chandigarh. 

● Honey has high concentration of sugar does not decay because bacteria can not survive in a solution of high osmotic strength as water is drawn out.

● Bacteria are useful for commercial as well as industrial application like fermentation,  production of vaccine, cleaning of oil  spills and producing other bioactive molecules. 

● Bacterial decomposition of biological material under anaerobic condition is called composting.

● The most extensive use of  molasses after fermentation is for producing Ethanol.

● Among fungi, virus, bacteria and protozoa the photographic nutrition is only found in Bacteria. 


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