Notes-Class-11-Science-Biology-Chapter-3-Kingdom Plantae-Maharashtra Board

Kingdom Plantae

Class-11-Science-Biology-Chapter-3-Maharashtra Board


Topics to be Learn : 

  • Introduction
  • Kingdom Plantae
  • Salient Features of Major Plant Groups under Cryptogams
  • Salient Features of Major Plant
  • Groups under Phanerogams
  • Plant Life Cycle and Alternation of Generations

Introduction : Plants can prepare their own food by the process of photosynthesis. Hence, they are called as producers on land.

Kingdom plantae is classified on the basis of characteristics like absence or presence of seeds, vascular tissues, differentiation of plant body, etc. ‘

Phanerogams : Phanerogarns are seed producing plants. These plants produce special reproductive structures that are visible.

Cryptogams : Cryptogams are spore producing plants. These plants do not produce seed and flowers. They reproduce sexually by gametes, however their sex organs are concealed.

Differences between sub-kingdoms Cryptogamae and Phanerogamae :

Differences between sub-kingdoms Cryptogamae and Phanerogamae :

Cryptogamae Phanerogamae
Non-flowering plants Flowering plants
Sex organs are concealed Sex organs are visible
These plants do not produce seeds These plants produce fruits and seeds
An ovule is not formed An ovule is formed
It is further divided into three divisions, viz Thallophyta, Bryophyta, Pteridophyta It is further divided into two divisions, viz Gymnosperms, Angiosperms


Thallophyta :

Algae : Algae belongs to division Thallophyta.

Salient features of algae:


  • Algae are mostly aquatic, few grow on other plants as epiphytes and some grow symbiotically.
  • Some algae are epizoic i.e. growing or living non-parasitically on the exterior of living organisms.
  • Aquatic algae grow in marine or fresh water. Most of them are free-living while some are symbiotic.


  • Plant body is thalloid 1.e. undifferentiated into root, stem and leaves.
  • They may be small, unicellular, and microscopic like Chlorella (non-motile), Chlamydomonas (motile).
  • They can be multicellular, unbranched, filamentous like Spirogyra or branched and filamentous like Chara.
  • Sargassum is a huge macroscopic sea weed which measures more than 60 meters in length.

Cell wall:

  • The algal cell wall contains either polysaccharides like cellulose / glucose or a variety of proteins or both.
  • Reserve food material: Reserve food is in the form of starch and its other forms.

Reproduction :

  • Reproduction takes place by vegetative, asexual and sexual method.

Life cycle :

  • The life cycle shows phenomenon of alternation of generation, dominant haploid and reduced diploid phases.
Accessory pigments of algae :

Accessory pigments of algae :

Various types of photosynthetic pigments are found in algae.

  • Chlorophyll-a (Essential photosynthetic pigment) is present in all groups of algae.
  • The accessory pigments are chlorophyll-b, chlorophyll-c, chlorophyll-d, carotenes, xanthophylls and phycobilins. Phycobilins are of two types, i.e. phycocyanin and phycoerythrin.


Chlorophyceae (Graen algea):

  • These are mostly fresh water (few brackish water and marine).
  • Plant body is unicellular, colonial or filamentous.
  • Cell wall contains cellulose.
  • Chloroplasts are of various shapes like discoid, plate-like, reticulate, cup-shaped, ribbon-shaped or spiral with chlorophyll a and b.
  • Reserved food is in the form of starch.
  • Pyrenoids are located in the chloroplast. .
  • Green algae like Chlorella are rich in protein, hence used as food even by space travelers.
  • Examples : Chlamydomonas, Spirogyra, Chara, Volvox, Ulothrix, etc.
Shapes of chloroplast & Forms of Green algae:

Green algae with their characteristic shapes of chloroplast:

  • Chlamydomorzas – Cup-shaped
  • Spirogyra - Spiral or ribbon shaped
  • Oedogonium - Reticulate
  • Zygnema - Stellate or Star-shaped

Forms of green algae:

  • Unicellular motile: e.g. Chlamydomonas
  • Unicellular non-motile: E. g. Chlorella
  • Colonial fonns: e.g. Volvox
  • Filamentous branched: e.g. Cladophora, Chara
  • Filamentous unbranched: e. g. Ulothrix, Spirogyra


Phaeophyceae (Brown algae):

  • These algae are mostly marine, rarely fresh water.
  • Plant body is simple branched, filamentous (e.g. Ectocarpus) or profusely branched (e. g. Petalonia).
  • Cell wall has cellulose, fucans and algin.
  • Photosynthetic pigments like chlorophyll-a, chlorophyll-c and fucoxanthin are present.
  • Mannitol, laminarin are stored food materials. Body is usually differentiated into holdfast, stalk called stipe and leaf-like photosynthetic organ called frond.
  • Many species of marine algae are used as food. e. g. Laminaria, Sargassum.
  • Some species are used for the production of hydrocolloids (water holding substances). e.g Ectocarpus, Fucus etc.

Reproduction in Phaeophyceae :

Reproduction in Phaeophyceae :

  • Vegetative reproduction takes place by fragmentation.
  • Asexual reproduction takes place by biflagellate zoospores.
  • Sexual reproduction: Isogamous, anisogamous or oogamous
  • The gametes are pyriform (pear shaped) and flagellated.


Forms of brown algae:

  • Simple, branched and filamentous: Sargassum, F ucus, Ectocarpus
  • Profusely branched: Laminaria, Dictyota, Kelps (Seaweed) .
Differentiate between Chlorophyceae and Phaeophyceae :

Differentiate between Chlorophyceae and Phaeophyceae :

Chlorophyceae Phaeophyceae
Photosynthetic pigments are chlorophyll-a, chlorophyll-b. Photosynthetic pigments are chlorophyll-a, chlorophyll-c and fucoxanthin
Reserve food is in the form of starch Reserve food is mannitol and lgminarin
Examples : Chlorella, Chlamydomonas, Spirogyra, Chara, Volvox, Ulothrix Examples : Ectocarpus, Sargassum, F ucus, Laminaria, etc


Rhodophyceae (Red algea):

  • Habitat: These are found in marine as well as fresh water on the surface, deep sea and brackish water
  • Plant body: Plant body is thalloid.
  • Photosynthetic pigments: Cells contain chlorophyll-a, chlorophyll-d and Phycoerythrin.
  • Cell wall: Cell wall is made up of cellulose and pectin glued with other carbohydrates.
  • Stored food: Stored food is in the form of Floridean starch.
  • Examples : Chondrus, Batrachospermum, Porphyra, Gelidium, Gracillaria, Polyszphonia, etc.
Reproduction in Rhodophyceae :

Reproduction in Rhodophyceae :

  • Vegetative reproduction occurs by fragmentation.
  • Asexual reproduction occurs by non-motile spores.
  • Sexual reproduction takes place by non-motile gametes, oogamous and accompanied by complex post fertilization developments.


Forms of red algae:  The red thalli of most of the red algae are multicellular, macroscopic. e.g. Gracilaria, Gelidium, Porphyra, Polysiphonia, etc.

Use of red algae : Red algae like Gelidium and Gracilaria obtain solidifying agent agar-agar which is used in tissue culture medium.

Importance of algae :

Importance of algae :

  • Many species of algae are used as food. For e.g. Chlorella (rich in cell proteins hence sed as food supplement even by space travelers), Sargassum, Lammarla, Porphyra, etc.
  • Alginic acid is produced commercially from Kelps.
  • Hydrocolloids like algin and carrageen are obtained from brown algae and red algae respectively.
  • ‘Agar’ which is used as solidifying agent in tissue culture is obtained from red algae like Gelidium and Gracilaria.
  • Brown algae like sea weeds are used a fodder for sheep, goat, etc.
  • Being photosynthetic, algae help in increasing the level of dissolved oxygen in their immediate environment.
  • Algae are primary producers of energy rich compounds which forms the basis of food cycles in aquatic animals.


Bryophyta (Bryon : moss ; phyton : plant) : include approximately 960 genera and about 25,000 species.

Members of Bryophyta are mostly terrestrial plants which depend on water for fertilization and completion of their life cycle. Hence, they are called ‘amphibians of Plant Kingdom’.

  • Mosses(bryophytes) and lichens are the first species to appear on barren land.
  • Bryophytes grow in moist soil but need water for reproduction. Hence, they flourish during rainy season.
  • After mosses, herbs, shrubs and trees may start inhabiting the area.
Characteristics of Bryophyta :

Characteristics of Bryophyta :

  • Mostly terrestrial, occurs on moist and shady places.
  • Non-motile forms present, except male gametes.
  • It shows root like structures i.e. rhizoids and absence of vascular tissue.
  • Rhizoids are unicellular in liverworts while multicellular in mosses.
  • Rhizoids absorb water and minerals and also help in fixation of thallus on the substratum.


Bryophytes are divided into two groups : liverworts and mosses.

Liverworts : Liverworts (Hepaticeae) are known as lower members of Bryophyta.

  • Gametophyte possesses flat plant body called thallus.
  • The thallus is green, dorsiventral, prostrate with unicellular rhizoids.
  • Examples: Riccia, Marchantia.
Life cycle of Bryophyta :

Life cycle of Bryophyta :

  • Life cycle of Bryophytes shows sporophytic and gametophytic stages.
  • They alternate with each other to complete their life cycle.
  • Gametophyte is haploid, thalloid or leafy and dominant. (photosynthetic, independent thalloid or erect phase)
  • Sporophyte is short lived, multicellular and depends totally or partially on gametophyte for nutrition and anchorage.


Reproduction in liverworts :

Reproduction in liverworts :

  • In liverworts, asexual reproduction occurs by fragmentation of thalli or with the help of specialized snuctures called as gemmae.
  • These are green, multiccllular, asexual buds which grow in receptacles called gemma cup located on thalli.
  • These gemmae detach from the thallus and germinate to form new individual.


Hornworts (Anthocerotae) : Hornworts are bryophytes which have flattened thallus that produces hornlike structures called as sporophytes. e. g. Anthoceros.

 Mosses (Musci) : These are advanced members of Bryophyta which possess erect plant body.

  • Gametophytic phase of the life cycle of Mosses (Musci) includes two stages namely; protonema stage and leafy stage.
  • The protonema is prostrate green, branched and filamentous (it is also called juvenile gametophyte). It bears many buds.
  • Leafy stage is produced from each bud.
  • Vegetative reproduction takes place by fragmentation and budding in secondary protonema.
  • The leafy stage has erected, slender stem like (Cauloid) main axis bearing spiral leaf like structures (Phylloid)
  • It is fixed in soil by multicellular branched rhizoids.
  • Leafy stage bears sex organs.
  • Examples : Funaria, Polytrichum, Sphagnum, etc.

 Q. Why Funaria is called amphibious plant?

Answer :

 Funaria belongs to division Bryophyta. It is a terrestrial plant but requires water for fertilization and completion of its life cycle. Hence, it is called as an amphibious plant.


Economic importance of Bryophytes :

Economic importance of Bryophytes:

  • Some mosses provide food for herbivorous mammals, birds, etc.
  • Species of Sphagnum, a moss; provides peat used as fuel.
  • Mosses are also used as packing material for transport of living materials because they have significant water holding capacity.
  • Mosses along with lichens are the first living beings to grow on rocks. They decompose rocks to form soil and make them suitable for growth of higher plants. .
  • Dense layers of mosses help in prevention of soil erosion, thus act as soil binders.


Pteridophyta (Pteron : feather, phyton : plant): The plants which do not bear flowers, fruits and seeds, but have true roots, stem and leaves belong to division Pteridophyta. The group has about 400 genera and 11,000 species.

  • These plants are cryptogams as they do not produce seeds and flowers.
  • They have primitive conducting system.
Characteristics :

Characteristics : Pteridophytes are known as first vascular and true land plants :

  • Habitat : Ptendophytes grow in moist and shady places. e.g. Ferns, Horsetail. Some are aquatic (Azolla, Marsilea), xerophytic (Equisetum) and epiphytic (Lycopodium).
  • Plant body: It is differentiated into root, stem and leaves.
  • Primary root: The primary root is short lived and is soon replaced by adventitious roots.
  • Stem: The stem may be aerial or underground. .
  • Leaves: This group contains plants with pinnate (feather - like) leaves. Leaves may be scaly (e.g. Equisetum), simple and sessile (e.g. Lycopodium), small (microphylls e.g. Selaginella) or large (macrophylls) and pinnately compound (e.g. Nephrolepis / Ferns).
  • Vascular tissues: In these members xylem consists of only tracheids and phloem consists of only sieve cells.
  • Secondary growth: Secondary growth is not seen in pteridophytes due to absence of cambium.
  • Alternation of generations: Pteriodphytes show heteromorphic alternation of generations in which the sporophyte is diploid, dominant, autotrophic and independent. Gametophyte is haploid multicellular, generally autotrophic and short lived.


Reproduction in Pteridophytes :

Reproduction in Pteridophytes:

  • Sporophyte: The sporophyte shows asexual reproduction and produces spores by meiosis from which the gametophyte develops.
  • Gametophyte: The gametophyte is haploid, recessive but independent and reproduce sexually. The product of sexual reproduction, i.e. zygote produces diploid sporophyte.
  • Spores: The plants are heterosporous (producing different types of spores), small microspores and large megaspores, while many are homosporous producing only one type of spore. Spores are produced in special multicellular structures called sporangia.

Other than normal modes of reproduction, Pteridophytes show the following methods of reproduction :

  • Apogamy: It is the development of the sporophyte without the fusion of male and female gametes. It arises directly from the gametophyte. Here, the sporophyte is haploid.
  • Apospory: It is the development of the gametophyte from any cell of the sporophyte other than the spores. Such gametophyte is diploid in nature.


Examples of Pteridophyta : Nephrolepis, Selaginella, Azolla, Marsilea, Equisetum, Lycopodium, Psilotum, Dryopteris, Pteris, Adiantum

Importance of Pteridophytes :

  • Pteridophytes are used for medicinal purpose and as soil binders
  • Many varieties are grown as ornamental plants.

Q. Why Pteridophytes are also known as vascular Cryptogams

Answer :

  • The reproductive organs of pteridophytes are hidden.
  • Pteridophytes do not produce flowers, fruits and seeds. They reproduce asexually by forming spores and sexually by forming gametes, hence they belong to Cryptogamae.
  • These plants possess a primitive conducting system. Thus, conduction of water and food occurs through vascular tissue.
  • Hence, Pteridophytes are also known as vascular Cryptogams.


Distinguish between Bryophyta and Pteridophyta :

Distinguish between Bryophyta and Pteridophyta :

Bryophyta Pteridophyta
Bryophytes are non-vascular cryptogams. Pteridophytes are vascular cryptogams.
Plant body is thalloid, i.e. not differentiated into root, stem and leaves. Plant body is divided into true root, stem and leaves.
The gametophyte is the dominant phase in the life cycle of Bryophytes The sporophyte is the dominant phase in the life cycle of Pteridophytes.
The sporophyte remains attached to the gametophyte. The sporophyte is never attached to the gametophyte.
The sporophyte is dependent upon the gametophyte for its nourishment. The sporophyte 1s not dependent upon the gametophyte.
Examples: Riccia, Marchantia, Funaria, etc. Examples : Nephrolepis, Equisetum, Lycopodium, etc.
Gametophyte of Bryophytes is haploid, dominant, photosynthetic, independent, thalloid or erect. Gametophyte of Pteridophytes is haploid, multicellular, generally autotrophic and short lived.


Sporophyte of Bryophytes is short lived, multicellular and depends totally or partially on gametophyte for nutrition and anchorage. Sporophyte of Pteridophytes is dominant, independent and vascular plant body.


Gymnosperms (Gymnos : naked, sperma : seed) : There are about 70 genera and 1000 living species of Gymnosperms in world. In India it is represented by 16 genera and 53 species.

General characters of Gymnosperms :

General characters of Gymnosperms:

  • Types: Most of the gymnosperms are evergreen, shrubs or woody trees.
  • Vascular tissues: They are vascular plants having xylem with tracheids and phloem with sieve cells.
  • Flower: These are primitive group of flowering plants producing naked seeds. Seeds are not covered by fruit i.e. ovary.
  • Body: The plant body is sporophyte. It is differentiated into root, stem and leaves.
  • Roots: The root system is tap root type. In some gymnosperms, the roots form symbiotic association with other life forms. Coralloid roots of Cycas show association with blue green algae and roots of Pinus show association with endophytic fungi called mycorrhizae.
  • Stem: In gymnosperms, stem is mostly erect, aerial, solid and cylindrical. Secondary growth is seen in Gymnosperms due to the presence of cambium. In Cycas it is usually unbranched, while in conifers it is branched. (e.g. Pinus, Cedrus).
  • Leaves: The leaves are dimorphic. The foliage leaves are green, simple needle like or pinnately compound, whereas scale leaves are small, membranous and brown.
  • Spores: Spores are produced by microsporophyll (Male) and megasporophyll (Female). Gymnosperms are heterosporous. The microsporophylls and megasporophylls are usually arranged in compact structures called cones or strobili.
  • The microsporangium (pollen sac) produces large number of spores (microspores or pollen grains) which are light in weight.
  • Each megasporangium (ovule) is surrounded by integuments. The ovule is orthotropous, i.e. upright.
  • Vegetative reproduction: Vegetative reproduction takes place with the help of bulbils.
  • Sexual reproduction: The pollination in Gymnosperms ts anemophilous (wind pollination) and direct as the pollen grains are received directly in the pollen chamber of the ovule.
  • Fertilization occurs through a pollen tube. This process is called siphonogamy.
  • Alternation of generation: Gymnosperms show a distinct heteromorphic alternation of generations.
  • The sporophyte is diploid, dominant, autotrophic, independent. While gametophyte is haploid, recessive and dependent.
  • Smallest gymnosperm : Zamia pygmaea

Economic importance

  • Cycas is grown as ornamental plant.
  • Pinus is used as source of pine wood, turpentine oil and pine resin.

Angiosperms (Angios : enclosed : vessel, Sperma : seed):

Salient features of angiosperms:

  • Habitat: Angiosperms is a group of highly evolved plants, primarily adapted to terrestrial habitat.
  • Alternation of generations: Angiosperms show heteromorphic alternation of generation in which the sporophyte is diploid, dominant, autotrophic and independent. The gametophytes (male or female) are recessive, haploid and dependent on the sporophyte.
  • Spores and Sporophylls: Angiosperms are heterosporous. Microspores (commonly called pollens) are formed in microsporangia (or anthers). They develop in highly specialized microsporophyll or stamens while megaspores are formed in megasporangia (or ovules) borne on highly specialized megasporophyll called carpel.
  • Flower: Besides the essential whorls of microsporophylls (androecium) and megasporophylls (gynoecium), there are accessory whorls namely, calyx (sepals) and corolla (petals) arranged together to form flowers.
  • Body: The body of sporophyte is divisible into root, stem and leaves. It has flowers, fruits and seeds.
  • Vascular tissues: Vascular tissues are well differentiated. Xylem shows vessels or tracheids, while phloem shows sieve tubes and companion cells.
  • Pollination: The pollination is indirect and maybe self or cross.
  • Sexual reproduction: There is typically double fertilization, one male gamete fusing with egg cell to form embryo and another fusing with secondary nucleus to form endosperm.
  • The zygote continues to develop within the ovule until seed is developed. The ovary simultaneously ripens into a fruit.


Wolffia is the smallest Angiosperm, 1mm in size and Eucalyptus grows to over 100 meters.

 Q. Ginkgo biloba is called as living fossil. Why?

Answer :

Ginkgo biloba is called as living fossil, because this plant is found in living as well as fossil form and the number of fossil forms is much more than the living forms.


Q. Write the similarities and dissimilarities of garden plants like Cycas, Thuja, Pinus, Sunflower, and Canna.

Answer :

Similarities : Plant body is divided into root, stem and leaves.

Dissimilarities :

  • In Cycas, Thuja and Pinus seeds are not enclosed within a fruit, whereas in Sunflower and Canna seeds are enclosed within a fruit.
  • Plants like Cycas, Thuja, Pinus show cones bearing microsporophylls and megasporophylls, whereas sunflower and Carma plant bear flowers.
  • In Cycas, Thuja and Pinus green, simple needle like or pinnately compound foliage leaves and brown membranous scaly leaves can be observed, whereas in Sunflower, Canna green foliage leaves can be observed.


Double fertilization : Double fertilization is a characteristic feature of angiosperms.

In this process one male gamete fuses with egg cell and another male gamete fuses with secondary nucleus, to form an embryo and endosperm respectively.

Two classes of Angiosperms :

Two classes of Angiosperms : Dicotyledonae and Monocotyledonae.

Dicotyledonae :

  • These plants have two cotyledons in their embryo.
  • They have a tap root system and the stem is branched.
  • Leaves show reticulate venation.
  • Flowers show tetramerous or pentamerous symmetry.
  • Vascular bundles are conjoint, collateral and open type.
  • Cambium is present between xylem and phloem for secondary growth
  • In dicots, secondary growth is commonly found.
  • e.g. Helianthus annuus (Sunflower).

Monocotyledonae :

  • These plants have single cotyledon in their embryo.
  • They have adventitious root system and stem is rarely branched.
  • Leaves generally have sheathing leaf base and parallel venation.
  • Flowers show trimerous symmetry.
  • The vascular bundles are conjoint, collateral and closed type.
  • Cambium is absent between xylem and phloem. Therefore in Monocots, except few plants secondary growth is absent.
  • e.g. Zea mays (Maize).

Monocot leaves : Canna, Grass

Dicot leaves : Hibiscus, Peepal, and Tulsi.


Noticeable differences between Gymnosperms and Angiosperms :

Noticeable differences between Gymnosperms and Angiosperms :

Gymnosperms Angiosperms
In gymnosperms, the seeds are naked. In angiosperms, the seeds are enclosed within the fruit.
Plants are evergreen, shrubs or woody trees. Plants are annual, biennial or perennial herbs, shrubs or trees, either woody or herbaceous.
Xylem is made up of tracheids only. Xylem is made up of vessels and tracheids.
Phloem is with sieve cells only. Phloem is with sieve tubes and companion cells.
Usually two types of leaves are present, i.e. green foliage leaves and scale leaves. Leaves are of usually one type only, such as green foliage leaves.
Double fertilization absent. Double fertilization occurs,


Q. Which of the following nuts will not be enclosed in fruits? What are the peculiar characteristics of these plants? Betel nut/ Areca nut, pine nut, walnut, almond, cashew nut, nutmeg.

Answer :

  • Pine nuts are edible seeds of pines which are not enclosed in a fruit. It belongs to class gymnospermae thus, seeds are not enclosed within the fruit.
  • Nuts like betel nut/ areca nut, walnut, almond, cashew nut, nutmeg will be enclosed in fruits. It is because these plants belong to class angiospermae in which seeds are enclosed within the fruit.

Characteristics of pine nuts :

  • Pine nuts are the edible seeds of the female cone of pine tree.

(Also refer Characteristics of gymnospermae):

Characteristics of betel nut/areca nut, walnut, almond, cashew nut, nutmeg :

  • The Betel nut / Areca nut is the fruit of the areca palm (Areca catechu). The seed is separated from the outer layer of the fruit and may be used fresh and dried.
  • Both almond and walnut are the edible seeds of drupe commonly called as nut.
  • The true fruit of the cashew tree is a kidney shaped nut that grows at the end of the cashew apple. During development of a fruit, peduncle expands and forms cashew apple. The kidney shaped true fruit contains a single seed, which is considered a nut.
  • Nutmeg is a seed which is commonly used as spice.

(Also refer Characteristics of angiospermae).


Various groups of vascular plants :

Various groups of vascular plants :

There are 3 groups of vascular plants:

  • Pteridophytes : Pteridophytes are the only cryptogams with vascular tissue.
  • Gymnosperms : Gymnosperms are the plants which possess naked seeds and also known as phanerogams without ovary.
  • Angiosperms : Angiosperms are the flowering plants in which the seeds remain enclosed within the fruits. Double fertilization is the unique feature of angiosperms.


Plant life cycle and alternation of generations:

Alternation of generations : The sporophytic and gametophytic generations generally occur alternately in the life cycle of a plant. This phenomenon is called alternation of generations.

  • The given figure indicates alternation of generation.
  • The life cycle of a plant includes two generations, sporophytic (diploid = 2n) and gametophytic (haploid = n)
  • Some special diploid cells of sporophyte divide by meiosis to produce haploid cells.
  • These haploid cells divide mitotically to produce gametophyte.
  • On maturation, gametophyte produces male and female gametes which fuse during fertilization and produce diploid zygote.
  • Diploid zygote divides by mitosis and forms diploid sporophyte.
  • Thus, sporophytic and gametophytic generations generally occur alternately in the life cycle of a plant.
  • Bryophytes and Pteridophytes show distinct alternation of generation.
  • In the life cycle of Bryophyta, gametophyte is the dominant phase
  • In the life cycle of Pteridophyta, sporophyte is the dominant phase.
Haplontic life cycle :

Haplontic life cycle :

  • In haplontic life cycle mitosis occurs in haploid cells.
  • It results in the formation of a single celled haploid or a multicellular haploid organism.
  • These forms produce the gametes through mitosis.
  • Zygote is formed after fertilization. This cell is the only diploid cell in the entire life cycle of the organism.
  • Thus, the same zygotic cell later undergoes meiosis.
  • This type of life cycle observed in some algae and fungi.
  • Haplontic life cycle is observed in many algae.


Diplontic life cycle :

Diplontic life cycle :

  • Here, mitotic division occurs only in diploid cells.
  • Gametes formed through meiosis are haploid in nature.
  • The diploid zygote formed after fertilization divides mitotically.
  • In this process, production of multicellular diploid organism or the production of many diploid single Cells takes place.
  • Animals show diplontic life cycle.
  • Diplontic type of life cycle is commonly observed in animals and all seed-bearing plants i.e. gymnosperms and angiosperms.


Haplo-diplontic life cycle :

Haplo-diplontic life cycle :

  • In haplo-diplontic life cycle, mitosis occur in both diploid and haploid cells.
  • These organisms undergo through a phase in which they are multicellular and haploid (the gametophyte), and a phase in which they are multicellular and diploid (the sporophyte).
  • It is observed in land plants and in many algae.
  • It is commonly observed in bryophytes and pteridophytes.


Most of the algae shows haplontic life cycle.

Some algae like Ectocarpus, Polysiphonia, kelps show haplo-diplontic life cycle.

Fucus shows diplontic life cycle.

Map :



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  1. Very clear notes thanks for this notes.

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