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Morphology of flowering Plants

 

INTRODUCTION

Morphology Of Flowering Plants, Chapter Notes, Class 11, Biology

      +    Morphology – (Morphe = form + logos = study). It deals with the study of forms and features of different plant organs like roots, stems, leaves, flowers, seeds, fruits etc.

      +    The body of a typical angiospermic plant is differentiated into :

            an underground root system

           an aerial shoot system.

            The shoot system consists of stem (including branches), leaves, flowers and fruits.

+    The roots, stems and leaves are vegetative parts, while flowers constitute the reproductive part.

Classification of  Plants

     

Depending upon their life span, plants are classified as –

      +    Annuals – Complete their life cycle in one year or singlerowing season or few weeks to a few months. They pass the unfavourable period in the form of seeds eg. Mustard, Pea.

  • Biennials – Complete their life cycle in two years-growing, vegetative and storing food in the first year, flowering and fruiting in the second year. They die off after producing flowers and fruits
    Radish, turnip, carrot are biennial in colder areas. They become annual in warmer places.
  • Perennials – Survives for several years. These plants usually bears flowers and fruits every year and do not die after producing flowers. eg. Mango, Banana,uava

Radicle comes out/arise from the seed coat in the form of soft structure and move toward the soil. It develops and forms primary root.

+  eneral Characters :

      +    Roots are non green, underground, (+) geotropic, (–) phototropic and (+) hydrotropic.

  • Roots do not bear buds.
  • Buds present for vegetative propagation in sweet potato (Ipomea) and Indian red wood (Dalbergia)

      +    Roots do not bear nodes and internodes.

      +    Roots have unicellular root hairs.

4 Types of Roots

 

Roots are of two types :

G  Tap root       G  Adventitious root

      +    Tap root : It develops from radicle and made up of one main branch and other sub branches.

      +    Adventitious roots : When root is originated from any other part of plant than radical. It is known as Adventitious root.

      Root System : 

      +    Root systems are of two type : (i) Tap Root System,                (ii) Fibrous Root System

      (i)  Tap root system - Primary root and its branches constitute tap root system. e.g., Dicot

      (ii) Fibrous root system – In some plant mainly in monocots, after sometime growth of tap root stop and than roots develop from other part of plant which are highly branched and fibrous and form fibrous root system.

 

REGIONS OF ROOTS

 

Morphology Of Flowering Plants, Chapter Notes, Class 11, Biology

Morphologically four distinct regions are present in roots.

      +    Root cap : It is terminal structure. It protects tender apex of root.

  • Meristematic zone : Cells of this regions are very small and thin walled. They divide repeatedly and increase cell number

      +    Elongation region : The cells proximal to meristematic zone undergo rapid elongation and enlargement and are responsible for rapid growth of roots.

  • Maturation region : Cells proximal to region of elongation gradually differentiate and mature. Root hairs are present in maturation zone.

 

Question for Morphology Of Flowering Plants, Chapter Notes, Class 11, Biology
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Which region of the root is responsible for the rapid growth of roots?
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MODIFICATION OF ROOTS

 

1.   Modified tap root for storage :

      +    Fusiform roots : These root are thicker in the middle and tappered on both ends. In this type of roots both hypocotyl and root help in storage of food. eg. Radish.

      +    Conical roots : These roots are thicker at their upper side and tapering at basal end. eg. Carrot.

  • Napiform : These roots become swollen and spherical at upper end and tappered like a thread at their lower end. eg. Turnip (Brassica rapa), Sugarbeet
  • Tuberous root : Such roots do not have regular shape and get swollen & fleshy at any portion of roots. egMirabilis.

2.   Nodulated root : Nodules are formed on branches of roots by nitrogen fixing bacteria, (Rhizobium). eg. Plants of leguminosae family (Papilionatae) – Pea.

 

3.   Respiratory roots : Halophyte or mangrove grow in oxygen deficient marshy area. Some branches of tap root in these plant grow vertically & comes out from soil. These roots are called pneumatophores through which air entered inside the plant. eg. Rhizophora, Heritiera, Sonaratia and other mangrove plant.  

 

Modification of adventitious roots :

      1.   Storage adventitious roots 

   Tuberculated root : When food is stored in these roots, they become swollen and form a bunch. eg. Sweet potato (Ipomea batata)

G   Fasciculated – Roots arise in bunch (cluster) from lower node of the stem and become fleshy eg. Dahlia, Asparagus.

G   Nodulose : In this type, tips of roots swell up. eg. Melilotus, Curcuma amoda. 

G   Beaded or moniliform : When root swells up like a bead at different places after a regular interval. eg. Vitis, Momordica (Bitter gourd), Portulaca.

   Annulated : Roots having series of ring like swellings eg. Psychrotia

                 

                Tuberous      Fasciculated roots           Moniliform                Nodulose           Annulated roots

2.    Stilt roots or brace roots : When root arises from lower nodes and enter in soil obliquely, known  as stilt roots eg. Maize, Sugarcane, Pandanus (screwpine) 

3.   Prop root or pillar roots : when root arises from branches of plant and grows downward towards soil. It function as supporting stem for the plant. eg. Banyan.

4.    Butteress root – Such roots appear from the basal part of stem and spread in different directions in the soil. eg. Ficus, Bombax , TerminaliaIt is a characteristic feature of tropical rain forest.

5.   Climbing roots – These roots arise from nodes and helps the plant in climbing. eg. Money plant (Pothos), Betel, Black pepper, Techoma.

6.   Foliar roots or Epiphyllous roots – When roots arise from leaf they are called as foliar roots.
eg. Bryophyllum, Bignonia.  

7.   Sucking or haustorial roots or Parasitic roots : In parasitic plant roots enter in the stem of host plant to absorbed nutrition from host. eg. Dendrophthoe, Cuscuta, Viscum.

 

  1. Assimilatory roots : The aerial roots of Tinospora and submerged roots of Trapa (Water chestnut) become green and synthesize food. Podostemon also has green assimilatory roots.
  2. Hygroscopic roots : These are found in epiphytes, specially in orchids and help in absorption of moisture from the atmosphere using special tissue called velamen. eg. Orchids, Banda
  3. Contractile roots : They shrink 60 – 70% of the original length and bring underground organ at proper depth in the soil e.g., corm of Crocus (saffron), Fresia.
  4. Root thorns : These are hard, thick and pointed thorns e.g. Pothos armatus.

12. Reproductive roots : These are fleshy, adventitious roots used for vegetative reproduction e.g., sweet potato (Ipomea batata), Dahlia.

13. Leaf roots : In Salvinia, one leaf of each node modifies into root like structure for balancing the plant in water.  

Morphology Of Flowering Plants, Chapter Notes, Class 11, Biology

 

FUNCTIONS OF ROOTS

  • Fixation (Primary function)
  • Absorption of water and minerals
  • Storage of food
  • Conduction of water
  • Photosynthesis and respiration

STEM

Stem is a part of plant which lies above from surface of soil i.e. it shows negative geotropic growth. It has nodes and internodes. Branches, leaf, flower bud and bracts are developed from nodes. Stem arises from plumule.

 

FORMS OF STEM

  •  
  • Caudex : It is unbranched, erect, cylindrical stout stem and marked with scars of fallen leaves. Crown of leaves are present at the top of plant. eg.: Palm
  • Culm : Stem is jointed with solid nodes & hollow internodes. eg. Bamboo (Graminae)
  • Excurrent : The branches arise from the main stem in acropetal succession and the tree assumes a cone like appearance e.g. Pinus, Eucalyptus, Casuarina, etc.
  • Decurrent (Deliquescent) : The lateral branches grow more vigorously and outcompetes the main trunk, giving a dome-shaped appearance, e.g., mango (Mangifera indica), shishem (Dalbergia sissoo) and banyan (Ficus bengalensis).

 

TYPES AND MODIFICATION OF STEM

 

+    Aerial stems (Epiterranean stem) :

      It may be reduced, erect and weak.

      +    Reduced – Stem reduced to a disc. eg., Radish, Carrot, Turnip.

  • Erect stem -  It is strong and upright e.g., maize, wheat, mango.
  • Weak stems – These are thin, soft and weak and need support. They can be upright or prostrate.

         Creepers – The stem creeps on earth and the roots arise at the nodes, e.g., Grasses, Strawberry, Oxalis.

       Lianas (Stem climber). Woody perennial climbers found in tropical rain forests are lianas. They twin themselves around tall trees to secure sunlight, e.g., Hiptage, Bauhinia vahlii (Phanera).

        Climbers – Plants are with long weak stem and have organs of attachment to climb the object. They may be of following type .

            w   Rootlet climbers – Roots produced at nodes help in climbing e.g., Tecoma, Pothos, Piper betal (pan).

            w   Hook climbers  – In Bougainvillea, Duranta and Carrisa, the thron is modification of axillary vegetative bud which helps in climbing. In Bignonia, terminal leaflet is converted into
hook.

  1. Tendril climbers – Tendrils are thread like structure which help the plants in climbing. Tendrils are modifications of :
  • Stem e.g., Vitis (grapevines), gourds, Passiflora (modified axillary bud).
  • Entire leaf e.g. Lathyrus sativus.
  • Leaflet e.g. Pisum sativum
  • Petiole e.g. Clematis, Nepenthes
  • Stipule e.g. Smilex.
  • Leaf apex e.g. Gloriosa
  • Inflorescence e.g. Antigonon.

        Twiners – The stem body twines around the support without any special organ of attachment. e.g., Cuscuta, Dolichos.

+    Sub-aerial modification :

  • Runner – When stem grows and spread on the surface of soil. Roots are developed at lower side and leaves from upper side from node eg. Cynodon dactylon (Doob grass), Oxalis
  • Stolon – A slander lateral branch arises from the base of main axis and after growing aerially for some time arch down ward to touch the ground. eg., Jasmine, Mint.
  • Sucker – The lateral branch originate from the basal and underground portion of the main stem grow horizontally beneath  the soil and come out  obliquely upward giving rise to leafy shoot.  eg. Pineapple, Chrysanthemum, Banana, Mint.
  • Offset – A lateral branch with short internode and each node bearing a rossette of leaves and tuft of roots at base. eg. Pistia, Eichhornea.

 

  • These modifications are also involved in vegetative reproduction. 

 

Question for Morphology Of Flowering Plants, Chapter Notes, Class 11, Biology
Try yourself:
Which type of stem modification grows horizontally beneath the soil and comes out obliquely upward to give rise to a leafy shoot?
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+    Underground modification :

      This type of modification occurs generally for food storage and vegetative propagation.

  • Tuber – The tips of underground branches become swollen in the soil. Eyes are found on then which are axillary buds and covered with scaly leaves. eg. Potato, Helianthus tuberosus
  • Rhizome – It is fleshy and horizontally stem found below in soil. Small nodes and internodes are found which are covered by scaly leaves. eg. Ginger, Turmeric, Canna, Banana. 
  • Corm – It is condensed structure which grow vertically under the soil surface. They are having spherical node and inter node eg. Colocasia, Alocasia, Zaminkand, Saffron, Gladiolus, Colchicum
  • Bulb – This stem is reduced and has disc like structure and surrounds with numerous fleshly scaly leaves. Many roots arise from its base. Food is stored in flashy leaves. They show apical growth eg. Onion, Garlic.

 

+    Special stem modification :

  • Phylloclade – It is green photosynthetic flattened or rounded succulent stem of some arid region plant with leaves either feebly developed or modified into spines e.g., Opuntia, Cactus, Euphorbia, Casuarina.
  • Thorn – It is modification of axillary bud, e.g., Bougainvillea, Duranta, Citrus. Thorns of Alhagi possess flowers, while thorns of Duranta bear leaves.
  • Cladode – Phylloclade usually having one or two internode long & succulent is called cladode, e.g., Asparagus, Ruscus.

 

  • Stem tendrill – it is a leafless, spirally coiled structure found in climbers. It is a modification of Axillary bud, e.g. Cucumber, Pumpkin, Vitis, Watermelon..

 

  • Bulbils – A condensed , axillary fleshy bud is called bulbils. It helps in vegetative reproduction. eg., Dioscorea, Globba, Agave, Oxalis.

 

FUNCTION OF STEM

 

The main function of the stem is spreading out branches bearing leaves, flowers and fruits. It conducts water, minerals and photosynthates. Some stems perform the function of storage of food, support, Protection and of vegetative propagation.

 

LEAF

Morphology Of Flowering Plants, Chapter Notes, Class 11, Biology

 

The leaf is a lateral generally flattened structure borne on the stem. The leaves develop from the nodes. Their main function is photosynthesis and food making. Axillary buds are found in its axil. Axillary bud later develops into a branch. All the leaves of a plant is known as phyllome. Leaves originated from shoot apical meristem and are arranged in acropetal order. 

 

+    Leaf is divided into 3 main parts :

  • Leaf base (Hypopodium) – 

     G   Leaves are attached to stem by leaf base.

G   In some plants, leaf base becomes swollen and is called pulvinus which is responsible for sleep movement  e.g., Cassia, mimosa, bean.

G   In some plants, leaf base expands into sheath (Sheathing leaf base), e.g., grasses and banana (monocots).

   When the leaf base partially encloses the stem, it is called semi amplexicaul e.g., Prickly poppy, Calotropis procera (Madar).

   It completely encloses the stem, it is called amplexicaul e.g., Sonchus, Polygonum.

  • Petiole (Mesopodium) 

      The part of leaf connecting the lamina with the branch of stem. Petiole help to hold the blade to light.

      In Eichhornia petiole swell and in citrus it is winged.

      Petiole is modified in tendrils in Nepenthes.

      In Australian acacia petiole is modified in phyllode.

      Long thin flexible petiole allow leaf blade to flutter in air, thereby cooling the leaf and bringing fresh air to leaf.

+   Lamina (Epipodium) :

               G   It is a broad and flatted part of leaf. Its main function is photosynthesis and transpiration.

+    Stipules :

Leaves of some plants have lateral appendages on either side of leaf base, known as stipules. If stipules are present in leaf it is called stipulated leaf, if it is absent then leaf is called exstipulated.

Stipules are of various types –

  • Free lateral – They are independently present on both sides of leaf base. eg. Hibiscus rosasinensis (China rose)
  • Interpetioler – When two leaves are meet oppositely at the node then nearest stipules of each leaf join with each other. In this way only two stipules of two leaves are found in place of four. eg. Ixora, Anthocephalus.
  • Intrapetioler – In this type both stipules of a single leaf join with each other to form a single stipule. eg. Gardenia
  • Foliaceous – These type of stipules form a leaf like structure. eg. Pea

 

  • Scaly – Stipules are dry, small and paper like. eg. Desmodium
  • Spiny – Stipules modified into spine. eg. Zizyphus (Beri), Acacia.
  • Ochreate – When both stipules of leaf combine together and form a tube like structure, It is called ochreate. eg. Polygonum
  • Adnate – Both stipules are attached with petiole. eg. Rose
  • Tendrillar – Stipules are modified into tendrils like structure. eg. Smilax

 

+    Duration of leaf :

  • Persistent / Evergreen – Leaves of such plants are found in all season and do not (fall) shed combindly. eg. Pinus, Saraca indica, Datepalm.
  • Deciduous – All leaves of such plants shed at the same time eg. Azadirachta.
  • Caducous – Leaves fall soon just after appearance or after opening of bud. eg. Cactus.

 

Question for Morphology Of Flowering Plants, Chapter Notes, Class 11, Biology
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Which part of the leaf is responsible for sleep movement in certain plants?
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VENATION OF LAMINA

The arrangement of veins and veinlets in leaves (Lamina) is known as venation. It is of 2 types

  • Reticulate : It is found in dicots. When the vein and veinlets form a network, the venation is known as reticulate. Exception – Calophyllum, Eryngium. It has parallel venation.
  • Parallel : It is found in monocots. When the veins run parallel to each other and do not form network the venation is termed as parallel. Exception – Smilax, Dioscorea, Alocasia, Colocasia. It has reticulate venation.

+    Reticulate venation :

 

+    Parallel venation :

In this type of venation, all veins run parallel to each other and they do not from network. They are of 2 types.

 

+    Simple and Compound Leaf :

  • Simple Leaf – A leaf which may be incised to any depth, but not down to the midrib or petiole, then this type of leaf called simple leaf. eg. Mango, Chinarose, Ficus, etc.
  • Compound leaf – A leaf in which the leaf blade is incised up to the midrib or petiole, thus dividing it into several small parts, known as leaflets. This type of leaf is known as compound leaf.

     It is of two types 

  • Pinnately compound leaf – In this type of leaf mid rib is known as rachis. Leaflets are arranged on both sides of rachis. eg. Neem.

     It is of following types -

       Unipinnate – In this type of leaf, division occurs only once and leaflets are directly attached on both sides of rachis.

       If the number of leaflet is even, then leaf is known as paripinnate. eg. Cassia fistula, Sesbania

       If the number of leaflet is odd, it is known as imparipinnate. eg. Rose, Neem. 

       Bipinnate – A twice pinnate compound leaf  eg. Acacia, Gulmohar, Mimosa.

       Tripinnate – A thrice pinnate compound leaf  eg. Moringa.

       Decompound – A compound leaf, which is more than thrice pinnate. eg. Carrot, Coriander.

 

  • Palmate compound leaf – In this type incision of leaf are directed from leaf margin to apex of petiole and all leaflets are attached on the upper end of petiole.

     It is of following types -

              Unifoliate – When single leaflet is found. eg. Lemon

              Bifoliate – When two leaflets are present. eg. Bauhinia, Regnelidium, Bignonia.

              Trifoliate – When three leaflets are attached. eg. Oxalis, Aegle, Trifolium

              Tetrafoliate – When four leaflets are attached to the petiole. eg. Marsilea.

             Multifoliate – when more than four leaflet are found, then leaf is called multifoliate palmate compound leaf. eg. Silkcotton.

      

+    Phyllotaxy :

      It is the pattern of arrangement of leaves on stem or stem branch. It is of following type –

  • Alternate or spiral – Single leaf arising at each node. eg. Chinarose, mustard & Sunflower, Cyprus rotandus,.
  • Opposite – Leaves occuring in pairs at the node, they may be –

     G Decussate : Leaves that stands at right angle to next upper or lower pair eg. Calotropis, Mussaenda.

     G Superposed : Successive pairs of leaves stand directly over a pair in the same plane eg. Psidium (guava), Ixora.

  • Whorled – More than two leaves at each node eg. Nerium, Alstonia.

           

                      Spiral                  Alternate             Opposite decussate    Opposite superposed       Whorled

+   Heterophylly – It is the occurrence of more than one type of leaves on the same plant. It is of three types –

      +    Developmental Heterophylly : Leaves of different forms and shape occur at different period or places on the same plant eg. Mustard, Sonchus, Eucalyptus.

  • Environmental Heterophylly : It is aquatic adaptation which is commonly found in rooted emergent hydrophytes. In this, submerged leaves differ from the floating and aerial leaves. eg. Limnophila, Heterophylla, Ranunculus aquatiles, Sagittaria.
  • Habitual Heterophylly : Due to habit mature leaves differ in their shape and incissions eg. Artocarpus (Jack fruit).

Morphology Of Flowering Plants, Chapter Notes, Class 11, Biology

MODIFICATION OF LEAVES

  • Leaf tendril – In it, whole leaf is modified into thin thread like structure which is called leaf tendril
    eg. Lathyrus aphaca (wild pea).
  • Leaflet tendril – When leaflet is modified into tendril like structure than it is called leaflet tendril.
    eg. Pisum sativum (Garden pea), Lathyrus odoratus (sweet pea)
  • Leaf spine – Leaves or any part of leaflet are modified into pointed spine. eg. Asparagus, Opuntia, Aloe, Argemone.
  • Leaf pitcher – Leaves of some plants are modified to pitcher shape. eg. Nepenthes, Dischidia. 
  • Leaf bladder – In some plant , leaves are modified into bladder like structure eg. Utricularia.
  • Leaf Hooks – In some plants terminal leaflets are modified into curved hooks for helping the plant in climbing. eg. Argemone, Opuntia, Aloe, Cat's nail (Bignonia unguis – cati)
  • Phyllode – In its, petiole becomes flat structure and function as normal leaf. eg. Australian acacia.
  • Flashy leaves – In onion and garlic food storing flashy leaves are present.

Arrangement of flower on floral axis is called inflorescence.

Racemose – In this type of inflorescence-

  1. Main axis continues to grow.
  2. Flower is not present at tip.
  3. Flowers are arranged acropetally

This is of following different types :

+   Raceme – When peduncle (main axis) is elongated and flowers are pedicellate.

     eg. Radish, characteristic feature of cruciferae family

     Compound raceme or panicle. eg. Gulmohar, Neem.

+   Spike – In it peduncle is elongated but flowers are bisexual and sessile.

     eg. Achyranthes 

     When peduncle is branched and each branch bear spike, like inflorescence then the small branch having flower is called spikelet and this arrangement is called as spike of spikelet. Characteristic inflorescence of family gramineae.

+   Catkin – In it peduncle is thin, long and weak, and flowers are sessile and unisexual. Peduncle is pendulus. eg. mulberry, betula, oak.

+   Spadix – In it peduncle is thick, long and fleshy and have small sessile and unisexual male and female flowers covered with one or more green or colourfull bracts known as spathe.

     eg. Colocasia, Maize, Aroids, Palms.

  • Corymb – In it peduncle is short and all flowers are present at same level because the lower flower has much long pedicel than the upper one eg. Candytuft (Iberis amara).
  • Compound corymb. eg. Cauliflower, 

     * In mustard corymbose raceme type of inflorescence is present 

+   Umbel – An inflorescence in which the flower stalks of different flowers are of more or less equal length, arise from the same point. At the base of flowers stalks, there is whorl of bracts forming the involucre.

     eg. Centella

+   Compound Umbel – eg., Coriander, Foeniculum, Cuminum.

     Characteristic feature of umbeliferae.

Question for Morphology Of Flowering Plants, Chapter Notes, Class 11, Biology
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Which type of inflorescence is characterized by a thin, long, and weak peduncle with sessile and unisexual flowers?
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+   Capitulum / Racemose head – In it the growth of peduncle is retarded and it become broad, flattened concave or convex. On it small flowers are found. These flowers are called floret. If all the flower of capitulum are same , then it is called homogamous. If two different type of floret, ray floret and disc floret are present in same inflorescence than it is known as heterogamous. In this type of inflorescence florets may be unisexual, bisexual and sterile. This inflorescence is surrounded by one or more involucre. It is most advanced type of inflorescence. eg. Sunflower, Zinnia, Marigold, Cosmos.

     Characteristic feature of asteraceae family.

Morphology Of Flowering Plants, Chapter Notes, Class 11, Biology

CYMOSE   

      In this type of inflorescence,

  1. Main axis show limited growth of peduncle.
  2. Peduncle terminates in a flower.
  3. Flowers are arranged in basipetal succession.

       It is of following types.

+    Uniparous cyme / Monochasial cyme - The peduncle ending in a flower producing lateral branch at a time of ending in flower. It is of two types -

  • Helicoid cyme – When all lateral branches developed on the same side on peduncle then it is called helicoid cyme. eg. Heliotropium, Saraca,
  • Scorpioid cyme – In it the lateral branch is alternately develop on left and right side. eg. Bignonia,

+    Dichasial or biparous cyme – In it peduncle ends in a flower, from the basal part of peduncle two lateral branches arise, which also end in a flower, now this same arrangement occur on these lateral branches.

      eg. Bougainvillea, Jasmine, Nyctanthes.

+    Multiparous cyme / polychasial – In it peduncle ends in a flower and from the base of it many lateral branches arise which also terminates in flower, this arrangement now also occur on these lateral branches. eg. Calotropis (Madar), Nerium, Asclepias.

 

SPECIAL TYPE OF INFLORESCENCE

  • Cyathium – The bracts or the involucre become fused to form a cup shaped structure on the margin. In the central part of cup shaped structure a single female flowers is found, which mature earlier. Female flower are surrounded by large no. of small male flowers. The male flower, which lie toward centre mature earlier than the flower which are towards periphery. This inflorescence is found in Euphorbiaceae family like Euphorbia, Poinsettia, Pedilanthus.
  • Verticillaster - A cluster of subsessile or sessile 3-9 flowers born on a dichasial cyme ending in monochasial cyme (scorpioid) in the form of condensed whorl on either side of the node. The verticels are further arranged in a racemose manner eg. Ocimum (Tulsi), Salvia. Characteristic inflorescence of labiateae family.
  • Hypanthodium – In it peduncle is modified in narrow cup like structure. At the base of cup female flowers develop while towards mouth male flower develops. All three types of flowers are present in this inflorescence. eg. Banyan, Peepal, Ficus species.

 

  • Mixed inflorescence – Some times flowers are arranged in both racemose and cymose manner on same peduncle called mixed inflorescence.  

       Mixed spadix – Banana             Cymose raceme or thyrsus – Grapes.

 

FLOWER

Morphology Of Flowering Plants, Chapter Notes, Class 11, Biology

Flower is defined as highly condensed and modified reproductive shoot.

Floral leaves are present on it.

In a flower there are 4 type of floral leaves are found.

  Sepal               Petal                Stamen           Carpel

 

SOME WORDS RELATED TO FLOWER

      +    Complete Flower – When calyx, corolla, androecium and gynoecium are present.

      +    Incomplete Flower – Flower with one of the four whorl missing.

      +    Bisexual Flower – Both gynoecium and androecium present in the same flower.

      +    Unisexual Flower – Androecium (staminate flower) or gynoecium (Pistillate flower) any one of them are  present in the flower.

      +    Monoecious Plant – When both male and female flowers are present on the same plant. eg. Cocos, Ricinus, Colocasia, Zea, Acalypha.

      +    Dioecious Plant – When male and female flowers are present on separate plant eg. Mulberry, Papaya.

      +    Polygamous Plant – When unisexual (male or female), bisexual and neuter flowers are present on the same plant eg. Mango, Polygonum.

      +    Monocarpic Plant – The plant which produces flowers and fruits only once in life eg. Pea, Mustard, Bamboo, Agave.

      +    Polycarpic Plant – The plants which produces flowers and fruits many times in life, eg. Pear, Mango,

      +    Cauliflory : Production of flowers on old stem from dormant buds eg. Artrocarpus, Ficus.

+    Symmetry of flower : Floral symmetry is of three type-

  • Actinomorphic / Radial / Regular – When a flower can be divided in two equal halves in any plane passing through the centre.  eg. Mustard, China rose, Datura, Chilli.
  • Zygomorphic / Bilateral – When a flower is divided into two equal halves only by one vertical plane, then it is called zygomorphic flower eg. Pea, Bean, Gulmohur, Cassia.
  • Asymmetrical / irregular – When the flower cannot be divided into two equal halves from any plane, then it is called asymmetrical flower. eg. Canna.

Internodal elongation in flower :

  • Anthophore – Internode between calyx and corolla is called anthophore. eg. Silane
  • Androphore – Internode between corolla and androecium is called androphore. eg. Passiflora
  • Gynophore – Internode between androecium and gynoecium is called gynophore. eg. Capparis.
  • Gynandrophore or Androgynophore – When both androphore and gynophore both conditions are found in same flower then this condition is called gynandrophore or androgynophore. eg. Cleome gynandra.
  • Carpophore – Elongation of thalamus beyond carpels. eg. coriandrum

Note : - Part of flower which lies near to mother axis is posterior part while the part which is far from mother axis is anterior part of flower. 

 

INSERTION OF FLOWER LEAVES

  • Hypogynous condition – When petals, sepals and stamens are situated below the ovary, the flower is called hypogynous and in this condition ovary will be superior. eg. mustard, Chinarose, Brinjal.
  • Perigynous condition – In it  thalamus grow upwardly and form a cup shaped structure. Gynoecium is situated in the centre and other parts of flower are located on the rim of the thalamus almost at the same level. It is called perigynous. The ovary here is said to be half inferior eg. plum, peach, rose.
  • Epigynous condition – The margin of thalamus grows upward enclosing the ovary completely and getting fused with it, the other parts of flower arises above the ovary, the ovary is said to be inferior and this condition is known as epigynous eg. Guava, Cucumber and ray florets of sun flower.   

       

Notes :

+   Bracts : Bracts are specialized leaves present in axis of flower.

  • Bracteate – The flower which have bract is called bracteate flower.
  • Involucre – The  whorl of bract surrounding peduncle is called involucre.
  • Involucel – Group of bracteole is called involucel.
  • Spathe – In flowers when large bract completely encloses whole inflorescence, then it is called spathe. eg. Banana, Maize.
  • Petaloid bract – When the size of bract of flower is greater than size of flower and these are of various coloured then it is called petaloid bract. eg. Bougainvillea.
  • Glumes – Small, dry, scaly bracts are called Glumes. eg. Wheat, Grass.

 

Question for Morphology Of Flowering Plants, Chapter Notes, Class 11, Biology
Try yourself:Which type of flower has a large bract that completely encloses the inflorescence?
View Solution

The outermost whorl of flower is called calyx. Each member of this whorl is called sepal. When all the sepals are free from each other, then it is called poly-sepalous condition eg. Mustard, Radish. When the sepals are fused each other, then it is called gamosepalous condition eg. Cotton, Datura, Brinjal.

  • In calyx of Mussaenda, one of the sepal enlarge and form a leaf like structure. It attracts the insects and thus act as advertisement flag.
  • In Trapa, calyx is modified into spines and helps in protection of fruit.
  • In Argemone spines are present on the surface of sepal which protect the flower bud.
  • In larkspur and Balsum, the posterior part of sepal is modified into a narrow tube. This structure is called sepal spur. Nectar is stored in it for insect attraction.
  • In asteraceae family, sepals are modified into hairy structure. It is called pappus. The pappus is a modified calyx and helps in dispersal of fruit.
  • Caducous – Sepals fall just at the time of opening of flower bud. eg. Poppy.
  • Deciduous – Sepals fall after pollination eg. Mustard
  • Persistant – If sepals do not fall and remain attached to fruit. eg. Tomato, Capsicum, Brinjal, Cotton, Datura.

* Sometime below calyx, a whorl similar to sepals is found which is called epicalyx. eg. Malvaceae family

 

The second whorl of flower is called corolla and each member of it is called Petals. When all the petals are free, then it is called polypetalous while when petals are fused, then it is called gamopetalous.

+    Forms of Corolla -

       POLYPETALOUS

  • Cruciform – 4 petals are present in it. The lower narrow part of petal is called claw while the outer broad part is called limb. These petals are arranged crosswise. eg. Radish, Mustard.
  • Caryophyllaceous – It consists of 5 petals the claw of petals are short and the limb of petals from right angle to the claw eg. Dianthus.
  • Rosaceous – It consist of 5 or more petals. Claws are absent in it and limbs are spread regularly outwards. eg. Rose, Coconut.

 

+    GAMOPETALOUS

  • Campanulate – Five petals are arranged like bell. eg. Tobacco, Raspberry, Campanula.
  • Funnel shaped or infundibuliform – Funnel like petals arrangement eg. Datura, Railway creeper.
  • Tubular – Petals are like tube eg. Disc florets of sunflower.

 

+    ZYGOMORPHIC POLYPETALOUS COROLLA -

       Papilionaceous – Five petals are present. It's posterior petal is largest and is known as standard or vexillum. Vexillum covers two lateral petals which are called as wings and the innermost basal petals are united to form a keel or carina. Both lateral parts covers the keel. eg. Pea, Gram, Arher

 

 

+    ZYGOMORPHIC GAMOPETALOUS COROLLA -

  • Bilabiate – The petal of gamopetalous corolla is divided into two lips. The place between two lips is called corolla mouth. eg. Ocimum, Salvia.
  • Personate – In this case the corolla is bilabiate but the two lips are near to each other eg. Antirrhinum
  • Ligulate – The upper part of corolla is long, flattened which is attached with short narrow tube. eg. Ray florets of sunflower.

 

+    AESTIVATION -

The mode of arrangement of sepals or petals in floral bud with respect to the other members of the seme whorl is known as aestivation. It is of following types -

  • Valvate – When petals or sepals in a whorl, just touches each other at margin without over lapping.
    eg. Calotropis, Mustard.
  • Twisted – In it one part of a petal covers adjacent petals and the other part is covered by posterior petal. One margin of appendages overlaps that of the next one and so on. It is known as twisted. eg. Cotton, Ladyfinger, Chinarose
  • Imbricate – When both margin of the one petal are covered by the others two petals and both margin of another one, covers other, Rest are arranged in twisted manner.

     It is of two types -

     G   Ascending imbricate – The posterior petal is innermost i.e., its both margins are overlapped. eg. Cassia, Bauhinia, Gulmohur etc.

     G   Vexillary or Papilionaceous – There are five petals the standard overlaps the two lateral petals which in turn overlap the smallest anterior petals. eg. Pea, Bean. 

  • Quincuncial – It is a modification of imbricate type. Out of the five petals, two are completely internal, two completely external and in the remaining petal, one margin is internal and the other margin is external. eg. Murraya, Ranunculus.

 

             Valvate                     Twisted                 Imbricate             Vexillary                                           Quincuncial

+   Perianth  

  • When there is no distinction between calyx and corolla the whorl is described as perianth.
  • Individual perianth segments are called Tepals. Green tepals are called sepaloid and coloured tepals are called petaloid. Tepals are free (polytepalous) or fused (gamotepalous). eg. Liliaceae and Graminae family

It is made up of one or more stamens. Each stamen consist of filament, anther and connective. Each anther is usually bilobed and each lobe has two chambers the pollensac. The pollen grains are produced in pollensac.

+    Attachment of filament to anther lobe : 

       The attachment of filament to another lobe is of 4 type -

  • Adnate – Filament runs through the whole length of the anther from the base to the apex. eg. Michelia (Champa), Magnolia
  • Basifixed – Filament is attached to anther by its base. eg. Datura, Radish, Mustard.
  • Dorsifixed – The filament is attached at the centre to the back of the anther. eg. Passion flower
  • Versatile – Filament attached to the back of the anther at a point only, thus the anther can swing freely. eg. Wheat, grass, maize.

 

+    Cohesion of stamens : 

       When the floral parts of similar whorl are fused, then it is called cohesion. When the stamens of an androecium are free from one another, it is called  polyandrous condition.

  • Adelphous : when stamens are united by their filament only, it is called adelphous. It is of following types –

        Monoadelphous – When all the filaments are united into a single bundle but anthers are free from each other. In this type of cohesion a tube is formed around the gynoecium which is called staminal  tube eg. Cotton, Hollyhock, Ladyfinger, Chinarose.

        Diadelphous – When the filaments are united in two bundles but the anther remains free eg. Gram, Pea, Bean

        Polyadelphous – When filaments are united into more then two bundles. eg. Citrus, Castor.

  •  Synandrous – When anthers as well as filaments of stamens are united through their whole length. eg. Colocasia, Alocasia, Cucurbitaceae family
  • Syngenesious – In it only anthers are united in bundle but filaments remain free eg. Compositae family

 

+    Adhesion of stamens : 

       When the stamens are attached to other parts of flower, then it is called adhesion of stamens.

  • Epipetalous – When stamens are attached to petals. eg. Brinjal, Datura, Tobacco, Sunflower, Potato.
  • Epiphyllous – When stamens are attached to tepals. eg. Onion, Lily.
  • Gynandrous – When stamens are attached to gynonecium either throughout their whole length or by their anther eg. Calotropis.

+    Note :

  • Didynamous – When four stamens are present, out of them outer two are long and inner two are short, then it is called didynamous. eg. Labiatae family, Salvia.
  • Tetradynamous – When there are six stamens and they are arranged in two whorls. In outer whorl, there are two short stamens while in inner whorl, there are four long stamens, this condition is called tetradynamous. eg. Cruciferae family, Mustard

 

Didynamous                        

Tetradynamous

 

  • It is female part of the flower comprising of the inner whorl of megasporophylls in the form of carpels bearing ovules. It consists of ovary, style and stigma. Ovary is the enlarged basal part, on which lies the elongated tube the style, the style connects the ovary to the stigma. The stigma is usually at the tip of the style and is receptive surface for pollen grains. The gynoecium may be monocarpellary or multicarpellary.
  • If only one carpel is present in gynoecium this condition is called monocarpellary.
  • If more than one carpel is present in gynoecium this condition is called polycarpellary.
  • If all the carpels in polycarpellary / multicarpellary condition are free, then condition is called apocarpous. eg., Lotus and Rose.
  • If all the carpels are fused together, then condition is called syncarpous. eg., Mustard and Tomato

 

       In syncarpous gynoecium four types of cohesion are found

  • When ovaries are fused, but stigma and style are separated with each other, eg. Dianthus, Plumbago
  • Ovary and style are fused, but stigma are not fused. Malvaceae family. Hibiscus rosasinensiscotton.
  • When stigma are fused but the ovary and style are free. eg. Calotropis, Cassia fistula, Nerium.
  • Carpels are completely fused. This condition is found in max. flowers, eg. Mustard, Radish, Tomato.

 

      The ovules are attached on ovary walls on one or more cushion called placenta. The arrangement of ovule within ovary wall is known as placentation. It is of following types –

  • Marginal : Marginal placentation is found in unilocular ovary. The placenta forms a ridge along the ventral suture of the ovary and the ovules are borne on this ridge forming two rows. eg. Leguminosae, Pea, Bean.
  • Parietal : This type of placentation is found in unilocular syncarpus ovary. In it the ovule develops on the innerwall of the ovary or on peripheral part. Ovary become bi or multilocular due to formation a false septum eg. Cucurbita, Argemoneand Cruciferae family (Mustard)
  • Axile : It is found in multicarpellary syncarpous gynoecium. The fusion margin of carpels grown inward and meet in the centre of the ovary. Thus an axis forms in the centre of ovary, thus ovary becomes multichambered. The ovules are born at the central axis. Number of these chambers are equal to the number of carpel eg. Potato, China rose, Onion, Lemon, Orange, Tomato
  • Free central : This type of placentation is found in syncarpous gynoecium. In it, the ovary is unilocular and the ovules are borne on the axis in the centre of the ovary. septum are absent in ovary. Placentation is axile in beginning. After sometimes walls of chamber destroy and only ovulated central axis left. eg. Primrose, Dianthus (Caryophyllaceae)
  • Basal : The ovary is unilocular and a single ovule is borne at the base of ovary. eg. Marigold, Sunflower (Asteraceae family). Poaceae family.
  • Superficial – This type of placentation is found in multicarpellary syncarpous gynoecium. The ovules are attached on the walls of locule eg. Nymphea (Water lily)

 

Question for Morphology Of Flowering Plants, Chapter Notes, Class 11, Biology
Try yourself:
Which type of placentation is found in unilocular syncarpous ovary where the ovules develop on the inner wall or peripheral part?
View Solution

      Fertilized and ripened ovary is fruit. A Fruit consist of (i) Pericarp (fruit wall),  (ii) seed.

      The seeds are protected inside fruit. But in some fruits. seeds are not found like in grapes, banana and such type of fruits are seedless fruit.

      If a fruit is formed without fertilization of the ovary it is known as parthenocarpic fruit.

       Pericarp : After ripening, the ovary wall change into pericarp. This pericarp may by thick and fleshy or thick and hard or thin and soft.

      Pericarp is differentiated in 3 layers

+    Epicarp :- It is the outermost layer, which is also called rind

+    Mesocarp :- It is the middle layer.

+    Endocarp : It forms the innermost layer.

     

      TRUE FRUIT : When the fruit is developed only from the ovary, the fruit is called as true fruit. eg. Mango, Coconut, Zizyphus

      FALSE FRUIT OR PSEUDOCARP : In some fruits, in place of ovary, some other parts of flower like thalamus, inflorescence, calyx are modified to form a part of fruit. These types of fruit are called false fruits. eg. Apple, Strawberry, Pear. 

Fruits are divided in three groups

        Simple           Aggregate               Composite

+   SIMPLE FRUIT :-

     These fruit develop from monocarpellary ovary or multicarpellary syncarpous ovary. Only one fruit is formed by the gynoecium. Simple fruits are of two types –

              Fleshy fruit    Dry fruit

      +    Fleshy Fruit:- These fruit develop from superior or inferior syncarpous gynoecium. These may be unilocular or multilocular. These fruits are indehiscent. Dispersal of seeds occur after pericarp is destroyed.

            Fleshy fruits are of following types :

                Drupe fruit :- These fruit develops from mono or multicarpellary, syncarpous, superior ovary. In these fruits endocarp is hard and stony so these fruits are also called stony fruits. eg. Mango, coconut almond, Peach walnut, plum. Brachysclereids are present in endocarp.

                  In mango edible fleshy part is mesocarp and the part where seed is protected is called as endocarp.

                  In ber, epicarp and mesocarp both are edible part.

                  The rind of Almond and walnut are endocarp and their edible part is seed.

                  In coconut epicarp is hard and thin while mesocarp is thick and consist of hard fibers The endocarp is hard and seed is protected in it. Endosperm is edible in coconut.

            G    Berry : These fruits develop from mono or multicarpellary syncarpous ovary. Ovary may be superior or inferior, Placentation is axile or parietal. In these epicarp is thin and seeds are embedded in fleshy part. Initially seeds are attached with placenta of fruit but after maturation these seeds are deteched with placenta and are spread randomly in fleshy part.

                   ?   Plants with superior ovary = Tomato, Grapes, Brinjal.

                   ?   Plants with inferior ovary = Guava, Banana

                  Date palm is one seeded berry. In it pericarp is divided into epicarp, mesocarp and endocarp. Epicarp is thin and soft while mesocarp is thick and fleshy and endocarp is thin like a membrane. Which is attached with seed.

                  Arecanut is one seeded fibrous fruit berry. When its thick fibrous layer is removed then seed comes out which is hard.

            G    Pepo - These fruit develops from tricarpellary, syncarpous and inferior ovary. This fruit is unilocular and have parietal placentation. These fruits are fleshy and spongy. sometime fruits are bitter in taste due to presence of tetracyclic triterpine in flashy pulp. eg. fruits of cucurbitaceae family.

                Pome - This fruit develops from bi or multicarpellary syncarpous inferior ovary. The rind and fleshy pulp are made up of thalamus. The main part of ovary is hard and dry and remain inside the fruit. Seeds are present in it. eg. Apple, Pear.

 

               Hesperidium : This fruit develops from multicarpellary, syncarpous, superior ovary. This fruit is specialy found in plants of Rutaceae family. eg. Orange, Lemon, Citrus fruit.

                  Epicarp of these is made up of thick rind which is leathery and many oil glands are found in  it. Mesocarp is white fibrous structure which is attached with epicarp. Membranous endocarp projects inward and form many chambers. Many glandular hairs are present on the inner side of endocarp. These glandular hairs are only edible parts.

               Balausta : It is a multilocular multiseeded fruit, which develops from inferior ovary. Its pericarp
is hard. Persistent calyx is arranged in the form of crown. Seeds are irregularly arranged
on placenta. Endocarp is hard. Testa is fleshy. This is the edible part of fruit. eg. Pomegranate (Punica granatum).

                Amphisarca : This fruit is multicarpellary and multichambered which develops from superior ovary. Pericarp is hard and fleshy placenta is found in them. The inner part of pericarp and placenta is edible part of fruit. Testa of seed is mucilegenous eg. wood apple (Aegle marmelos), elephant apple.

 

      +    Simple Dry Fruit - Pericarp of simple dry fruit is hard and dry and not differentiated into epicarp, mesocarp and endocarp. Such fruits are called dry fruit.

            Simple dry fruits can be divided into following three groups :

               Indehiscent          Dehiscent                Schizocarpic

      +    Indehiscent fruits : These simple dry fruits are generally of small size and single seeded pericarp does not rupture even after maturity.

               Cypsela : It is a small, single seeded dry fruit which develops from bicarpellary, syncarpous inferior ovary. Pericarp and seed coat are free from each other. In these fruits a bunch of hair is attached with the fruit which is known as Pappus. Pappus helps in fruit dispersal. eg. Compositae family Plants.

               Caryopsis : These are small, single seeded dry fruits. It develop from monocarpellary, superior ovary. Pericarp of these fruits is fused with the seed coat and form a joint surface. These fruits are present in family gramineae. Wheat grain or rice grain is a fruit.

               Achene : These are single seeded fruit which develops from monocarpellary superior ovary. In it, pericarp is free from the seed coat eg. Clematis, Mirabilis, Boerhaavia

               Nut : This is a single seeded fruit which develop from monocarpellary syncarpous superior ovary. In it pericarp is hard eg. Quercus (oak), Anacardium occidentale (Cashewnut) Trapa, (Water chest-nut), Litchi.

                  In Litchi epicarp and mesocarp is fused and give leathery apperence. Endocarp is membrane like thin. Outer seed coat grows forward and forms an additional coat around the seed which is called as aril. In mature fruit, this aril is fleshy and is only edible part.

               Samara : These are dry indehiscent one seeded feathery fruit. It develops from bi or tri carpellary, syncarpous and superior ovary. The main character of these fruits is wing like structure develops from its pericarp which helps in dispersal. eg. Holoptelia.

 

     In Shorea robusta wing develops from calyx instead pericarp and these fruit are called samaroid.

      +                Dehiscent Fruits : After ripening pericarp are ruptured and seeds are dispersed outside.

         Legume or pods : These fruits develop from monocarpellary, unilocular, superior ovary. It is generally long and multiseeded fruit. Dehiscense of fruit occurs at both sutures i.e. Dorsal and ventral side. Dehiscence start from apex and reaches to basal part. eg. Pea, Beans.

            When only one or two seeds are present in fruit, then it is also called as pod.

         Follicle : It is also multiseeded fruit which develops from superior unilocular, monocarpellary ovary but the dehiscence of it occur only at ventral suture. eg. Asclepias, Rauwolfia, Vinca, Michelia (Champa), Delphinium.

         Siliqua : This fruit develops from bicarpellary, syncarpous superior ovary with parietal placentation. Dehiscence occurs at both dorsal and ventral suture and starts from lower part and proceeds upward. Due to formation of false septum ovary become bilocular. On false septum, seeds are attached, This type of fruit is found in Cruciferae family. eg. Mustard.

     G    Silicula : A short broad siliqua is known as Silicula. It is also found in Cruciferae family. eg. Candytuft (lberis amara), Capsella,

         Capsule : This is dry multichambered and multiseeded fruit and develop from multicarpellary syncarpus, superior ovary. In it, Axile placentation is found and dehiscence occurs by various methods. Poricidal (Poppy), loculicidal (cotton), septifragal (Datura), septicidal (Lineseed).

 

  • Schizocarpic fruit : It is a multiseeded fruit. After ripening, it is devided into mericarp and seeds come out after destruction of pericarp. The fruits develop from mono or bi or multicarpellary superior or inferior ovary. The mericarp contains one or two seeds.

       Lomentum : It develops like legume. Fruits are constricted or divided in one seeded mericarp, after maturity these are separated with each other. Eg Tamarind, Cassia fistula, Mimosa pudica, Archis hypogea, Desmodium.

       Cremocarp : It is a double seeded fruit and develops from bicarpellary, syncarpous, inferior ovary. On maturation, it dehisces from apex to base in such a way that two mericarp forms and each contain one seed. These mericarp are attached with carpophore. Carpophore is the extended part of receptacle. eg. Coriander, Cuminum, Foeniculum.

       Regma : This fruit develops from tri to pentacarpellary, syncarpous superior ovary. In it three locules are present and its fruit is breaks into three one seeded part. Each part is known as coccus. At the outer end of pericarp, spines are found. eg. Euphorbiaceae family, Castor has three cocci Geranium has 5 cocci.

       Carcerulus : It is a dry fruit which develops from multi carpellary or bicarpellary, syncarpous, superior ovary. Number of mericarp is more than locules because of formation of false septum. It divides into four one seeded locules. eg. Ocimum (Basil), Salvia.

          In hollyhock and abutilon (family malvaceae), the no. of locules is more than four

       Utricle : It is a single seeded fruit which has thin membrane. It dehiscence generally from cap. It develops from bicarpellary, unilocular, syncarpous, superior ovary. eg. Achyranthes, Amaranthus.

      Double Samara : It develop from bicarpellary syncarpous superior ovary. Pericarp develops into two wings. On maturation it divides in two single seeded mericarp eg . samara , acer.

 

+   AGGREGATE FRUIT :-

      These fruits develop from multicarpellary apocarpous ovary. Because in apocarpous ovary, each carpel is separated from one another, therefore it forms a fruitlet. These fruits are made up of bunch of fruitlets which is known as etaerio.

      +    Etaerio of follicles : Each fruitlet is a follicle. eg. Calotropis, Catharanthus, Magnolia

      +     Etaerio of achenes : In this aggregate fruit, each fruitlet is an achene. eg. Rananculus, Strawberry, Rose, Lotus

      +    Etaerio of berries : It is an aggregate of small berries. eg. polyalthia, Annona squamosa (Custard-apple). In etaerio of Anona all the berries are arranged densly on thalamus.

  • Etaerio of drupes : In this type of fruit, many small drupes develop from different carpels. eg. Raspberry

 

Question for Morphology Of Flowering Plants, Chapter Notes, Class 11, Biology
Try yourself:
Which type of aggregate fruit is formed when each fruitlet is a follicle?
View Solution

             Etaerio of Follicles           Etaerio of Achenes                                     Etaerio of Berries              Etaerio of Drupes 

+   COMPOSITE FRUIT :-

      All composite fruits are false fruits.

      This type of fruit differ from aggregate fruit that in place of single ovary many ovaries and other floral parts combine together to form fruit. In composite fruits, generally whole inflorescence is modified into fruit. These are of two types.                                

      +    Sorosis : This fruit develops from spike, spadix or cartkin inflorescence. Peduncle become thick spongy and woody. eg. Jack fruit, Pandanus (screwpine), Pineapple

            In jack fruit (Kathal) pistillate flowers are developed around the peduncle. In fruit formation pericarp become spongy and fused.

            In Pine apple peduncle bracts and perianth become fleshy. Due to the fusion of perianths of flower a composite fruit is formed.

            In mulberry perianth become fleshy and axis of every flower becomes thick, sweet and fleshy and are edible.

  • Syconus : This fruit develops from hypanthodium inflorescence.  eg. Ficus species like fig, Peepal

 

            Geocarpic fruit : When fruit development occurs inside soil e.g. ground nut

 

  • The seeds falling directly under the mother plant have to germinate and develop under limited food supply and space. To overcome this problem, the fruits and seeds have developed several special devices for wide dispersal.
  • The natural agents like wind, water, animals and even mechanism of dehiscence in some fruits, help the seeds and fruits to disperse from one place to another, and to long distances from the parent plant.

+   WIND (Anemochory) :

  • In the species where the seeds are light in weight or have some accessory part to help dissemination, are dispersed by the air current.
  • The seeds of Drum-stick and Cinchona, and fruits of yam, maple and sal tree, are having appendages in the form of thin, flat and membranous wings, which help them to float in the air and be carried away to long distances.
  • In the members of Asteraceae, the calyx is modified into hair like structures called pappus. They persist in fruit and open out like umbrella, helping the seeds to float in the air.
  • In poppy and prickly poppy (Argemone), the fruit dehisces and seeds are thrown out to a distance away from the parent plant. (Censor mechanism)
  • The seeds of Calotropis, Alstonia and cotton are provided with hair and cover sufficient distances alongwith the wind.
  • The seeds of orchids and some grasses are very small and light in weight and may be easily carried away by wind to far off places.
  • In fruits of physalis swollen persistant calyx is present and fruit can easily be carried out by air.
  • Some plant like chenopodium, amaranthus etc. are uprooted after drying and carried away by wind and seeds are dispersed distantly. These plants are known as tumbler weed.

+   WATER (Hydrochory)  :

       +   The fruit and seeds with specialised devices which may be in the form of spongy and fibrous outer walls as in coconut and spongy thalamus as in lotus, and small seeds with airy aril as in water lily, float very easily in water and are carried away to long distances with the water current.

+   ANIMAL (Zoochory) :

  • The fruit and seeds with hooks, spines, bristles, stiff hair, etc., get attached to the body of animals and are carried away by them to distant places.
  • Fruits of Xanthium and Urena bear curved hooks.
  • Spear grass has a bunch of stiff hair.
  • Tribulus has sharp and rigid spines.
  • Boerhaavia has sticky hair, which help their dispersal by animals. In Martynia two curved hooks are present.
  • The edible fruits like guava, grape, fig and plum are dispersed by birds and even human beings by feeding on them and passing out undigested seeds with faeces or by carrying them to other places for later feeding.

Propagation of new plant by any plant part other than seed is known as vegetative propagation. The structural unit that is employed in place of seed for the propagation of new plants is called propagule. In Angiosperms any part of the plants – roots, stems and leaves used for vegetative propagation.

+    Natural Vegetative propagation :

      +    By roots :- Modified tuberous root of Sweet potato (Ipomoea batatas), Asparagus, Tapioca, Yam, Dahlia and Tinospora can be propagated vegetatively when planted in soil.

            In some plants adventitious buds develop on the ordinary roots like-Dalbergia sisso, Populus, Guava, Murraya, Albizzia lebbek etc. which grow to form new plants.

            The buds present on the roots grow into leafy shoot above the ground is called Slips.          

  • Under ground Stem :- In some plants under ground modified stem such as –

Rhizomes – Typha, Canna, Ginger, Turmeric, Lotus, Musa etc.

Corm – Gladiolus, Colocasia, Crocus, Amorphophallus, Alocasia etc.

Bulbs – Onion, Garlic and Lilies

Tubers – Potato, Helianthus tuberosus etc. which grow to form a new plants.

      +    Sub aerial stem :

               Runners – Cynodon, Oxalis and Centella

               Stolon = Fragaria (Strawberry) & Vallisneria

               Sucker – Mint and Chrysanthemum.

               Offset – Pistia, Eichhornia (water hyacinth) etc.

      +    Aerial stem - Opuntia 

      +    Leaves :- Some plants produce adventitious buds on their leaves e.g., Bryophyllum, Begonia, Streptocarpus, Saintpaulia. These buds remains dormant, when the leaves attached with plants but after separation, when it comes in contact with moist soil develop new plantlets [buds] which form new plants.

     +    In Kalanchoe, plant whole portion of leaf blade regenerate a new plant.

     +    In some of the plants, fleshy axillary buds develop from axis of leaves are called Bulbils

            Example – Dioscorea, Oxalis, Dentaria, Globba, Agave, Lilium.

     +    There are special type of fleshy buds develop in Aquatic plant are called Turions.

            Example – Potamogeton, Utricularia.

+    Artificial Propagation :

      +    Cutting :- A cutting is separated portion of root, stem or leaf which is used for propagation. Some time the stem cutting are treated with rooting hormone [IBA, IAA or NAA] for proper development of adventitious roots e.g., Sugarcane, Rose, Croton, Tapioca, China rose (Stem cutting) Lemon, Tamarind (Root Cutting) etc.

            [Favourable time for cutting - Rainy season]

      +    Grafting :- In this method, parts of two plants are joined in such a way that they grow as one plant. Grafting is done between two closely related dicotyledonous plants having vascular cambium. The rooted supported portion of one plant called Stock is joined with a twig of another plant called Scion. Generally, the root stock belong to wild variety which is resistant to disease & pest. The scion is derived from the plant possessing better characters. In grafting, the stock and scion cuts are marked in such a oblique manner so that they fix with each other. This joint is covered with clay or a layer of wax. Within a few days, tissues of stock and scion combined together and to form a new plant e.g., Grafted Mango, Roses, orange, Seedless Grapes and Guava, Apple, Pear.

            Types of Grafting –

              Tongue/Whip grafting                       Wedge grafting

              Crown grafting                                  Side grafting

              Approach grafting

      +    Bud grafting :- This method is similar to grafting except that scion in this case consist of a bud along with some portion of bark having intact cambium.

            Generally bud grafting is done during the rainy season e.g., Roses, Peach.

 

      +    Layering :- This method is used in those plants which are having flexible long branches. In this method, first roots are artificially induced on the stem branches then are detached from the parent plants for propagation. There are two common types of layerings.

                Mound/Ground Layering – This method is only utilized in herbaceous plants. In this method, the lower branch of stem is bent down and partially defoliated and injury is made on defoliated part. It is covered by thin layer of moist soil in such a way that the growing tip of the branch remains above the soil surface. After a few days the pegged portion developos adventitious roots. Then rooted branch cut and separed from parent and grown into new plant e.g., Jasmine, strawberry, Raspberry etc.

               Air Layering or Gootee –

                  This method is commonly employed in case of shrubs and trees 
which do not possess branches near the ground. In this method a ring of bark is removed [girdled] from the aerial branch. This girdled portion is covered with moist grafting clay [2 parts clay + 1 part cow dung + some pieces of hay + cotton + water] and wrapped with a polythene sheet.

                  This wrapped portion of the branch is called gootee. Inside the gootee roots developed within a period of one or two month(s) e.g., Litchi, Pomegranate, orange, Lemon and Bougainvillea, Guava etc.

+  Merits of Vegetative propagation : 

+    It is good for the multiplication of seedless plants e.g. Banana, Sugarcane, Pineapple and seedless Orange and Grape.       

+  It is the fastest method of reproduction.

+  By grafting, desirable quality of fruit/flower/seed can be obtained.

+  Plants with long seed dormancy or poor seed viability or poor seed can be propagated vegetatively e.g., Cynodon dactylon (Lawn, Doob or Bermuda grass).

+    The greatest  advantage of this method is that a Biotype of plant (original plant) can be retained & multiplied indefinetly without any change or variation.

+  Good quality and better yield varieties can be preserved for a long duration in off site collection, herbarium, botanical gardens etc.

+   It produce 100% genetically similar to their parents i.e., clone.

+  Demerits of Vegetative propagation : 

      +   Diseased parents always give diseased clone.       

      +   Clone undergoes degeneration due to the absence of sexual reproduction.

      +   Vegetative organs can not be preserved for long duration like culms of Sugarcane.

      +    Vegetative propagatory organs or structures cannot be safely and easily stored as comparison to seeds. They are easily decomposed and attached by various pathogens like Bacteria, Virus, Fungi.

      +   Do not cause any variation in plantlets, thus decrease in the adaptation power.

      +   There is absence of dispersal mechanism. Vegetative propagation in a particular area causes overcrowding. It results in intraspecific competition.               

 

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Morphology Of Flowering Plants, Chapter Notes, Class 11, Biology

MORPHOLOGY OF ANGIOSPERM

+    Arrangement of flowers on peduncle and study of flowers is called Anthology.

+    National flower of India is Lotus (Nelumbo nucifera)

+    Longest styles are found in maize.

+    Longest inflorescence is in Agave (12m),

+    In Mussanda, One (odd) sepal is enlarged to form a leafy structure called Advertisement Flag.

+    National fruit of India is Mango (Mangifera Indica)

+    Largest fruit and largest seed is of Lodoicea maldivica (double coconut, weight is 18 Kgs.)

+    False nuts are Coconut (drupe), Areca nut (Berry), Pea nut or Ground nut (Lomentum), Walnut (drupe) and Chilgoza (seed)

+    Dispersal of fruits and seeds by ants is called myrmechory eg. Ulex and Trillium (seeds).

+    Monophyllea is a plant with single leaf.

+    Welwitschia (a gymnosperm) is a plant with two leaves throughout the life.

+    Victoria regia has broadest leaves each with a diameter of 1.5–1.8m.

+    Leaves are longest in Raphia vinifera (10–15m)

+    Largest bud is cabbage.

+    Shruby climbers which climb with the help of hooks are called Stragglers eg. Bougainvillea, Artobotrys.

+    Marine angiosperm is Zostera.

+    Smallest angiosperm is Wolffia (less than 0.1 mm) and largest or tallest angiosperm is Eucalyptus regnans (height more that 114 m or 375 ft)

  • Plants with roots only are podostemon, Arceuthobium, Rafflesia and Sapria.
  • Maize (Zea mays) has largest stigma and style.
  • The sterile pistil is called pistalloide.
  • State tree of Rajasthan → Prosopis cineraria.
  • State flower of Rajasthan → Rohira (Tecomela undulate)
  • National tree of India → Ficus bengalansis
  •  
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FAQs on Morphology Of Flowering Plants, Chapter Notes, Class 11, Biology

1. What is morphology in plants?
Ans. Morphology is the branch of biology that deals with the study of the form and structure of living organisms. In the case of plants, morphology refers to the study of their external structure, including the roots, stems, leaves, flowers, and fruits.
2. What is the significance of studying the morphology of flowering plants?
Ans. The study of the morphology of flowering plants is crucial for understanding their classification, evolution, and adaptation to different environments. It helps in identifying and differentiating different plant species by their external features, which is essential for research, agriculture, and horticulture.
3. What are the different parts of a flower?
Ans. The different parts of a flower include the calyx, corolla, androecium, and gynoecium. The calyx is the outermost whorl of the flower and consists of sepals. The corolla is the second whorl and consists of petals. The androecium is the third whorl and includes the male reproductive organs, stamens, and anthers. The gynoecium is the innermost whorl and includes the female reproductive organs, pistil, and stigma.
4. How do the roots and stems differ in morphology?
Ans. The roots and stems differ in morphology in several ways. The roots are generally underground, and their main function is to anchor the plant and absorb water and nutrients from the soil. They are usually long, slender, and unbranched, with root hairs for increased surface area. In contrast, the stems are generally above ground and support the leaves, flowers, and fruits. They are usually thicker and more rigid than roots, with nodes and internodes that give rise to leaves and branches.
5. What is the role of fruits in the morphology of flowering plants?
Ans. The fruits are the mature ovaries of flowering plants and play a crucial role in their reproduction and dispersal. After pollination and fertilization, the ovules develop into seeds, and the ovary wall develops into a fruit. The fruits protect the seeds, aid in their dispersal, and provide nutrients for their germination and growth. The morphology of fruits is diverse, ranging from fleshy fruits like apples and berries to dry fruits like nuts and grains.
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