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State Board · Class 11 · Biology

Lesson 9: Morphology of Flowering Plants

7 concepts · 56 practice questions with answers · Free to read

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Habitat groups and the root

Link to Std 9–10

In Std 6 you recognised the outer parts of flowering plants; here we study the types and modifications of root, stem, leaf, flower, fruit and seed.

From daily life

Plants live in different places – ponds, deserts, seashores; the root holds them in place and searches for water.

Simple definition

Angiosperms by habitat: hydrophytes, xerophytes, psammophytes, lithophytes, halophytes. Root = descending axis; no nodes; positively geotropic and hydrotropic, negatively phototropic.

Root and habitatMaturationRoot-hair zoneElongationMeristematicRoot capRegions of a rootHabitat groupsHydrophyteswater – HydrillaXerophytesdesert – OpuntiaPsammophytessand – ElymusLithophytesrock – CladopusHalophytessaline – RhizophoraTap root (dicot)Fibrous (monocot)Tap = from radicle; adventitious = from other parts

In the figure : Regions of a root, habitat groups and root systems.

Rule 1 : Habitat groups — Hydrophytes in water (Hydrilla); xerophytes in dry regions (Opuntia); psammophytes in sand (Elymus); lithophytes on rock (Cladopus); halophytes in saline soil (Rhizophora – mangrove).

  • Easy : Hydro = water; xero = dry; halo = salt.
  • Medium : Hydrophytes have root pockets instead of root cap (Pistia).
  • Exam-type (CET) : Psammo = sand; litho = stone.

Rule 2 : Regions and types of root — From the tip: root cap (protection, graviperception; starch) → meristematic → elongation → root-hair zone (absorption; replaced every 10–15 days) → maturation (lateral roots, conduction). Tap root = from the radicle (dicots); adventitious/fibrous = from other parts (monocots: maize, wheat). Functions: anchorage, absorption, conduction.

  • Easy : Root cap makes the apex subterminal.
  • Medium : Root hairs are unicellular and short-lived.
  • Exam-type (CET) : Tap = radicle; fibrous = base of stem.
Remember

From the tip: Cap → Meristem → Elongation → Hair → Maturation.

Common mistake and CET trap

‘Growth is at the very tip of the cap’ is wrong (behind it). Trap: ‘monocots have tap root’ is wrong.

Shortcut

Memory clue : "C-M-E-H-M: Cap, Meristem, Elongation, Hair, Maturation".

Spot the difference

PointTap rootFibrous
OriginRadicleStem base
PlantsDicotsMonocots
ExamplePeaMaize, wheat

Practice questions

Easy
  1. 1Example of halophyte.
  2. 2What is a xerophyte?
  3. 3Function of root cap?
Medium
  1. 4Where are root hairs?
  2. 5Example of tap root.
  3. 6Adventitious root arises from?
Challenging
  1. 7Where is root pocket?
  2. 8Root vs stem.
Show answers (try them yourself first)
  1. 1Rhizophora (mangrove).
  2. 2Plant of dry regions.
  3. 3Protects tip; mucilage; graviperception.
  4. 4Root-hair zone (epiblema).
  5. 5Pea, sunflower.
  6. 6Parts other than radicle.
  7. 7In hydrophytes (Pistia).
  8. 8Root has no nodes, not green, grows downward.

Modifications of roots

From daily life

Carrot, radish and beet are stored roots – roots that took a special job beyond their usual one.

Simple definition

A root changed for a special job is a metamorphosed root. Types: storage, respiration, support and special functions.

Root modificationsRoot modificationsFusiformradishConicalcarrotNapiformbeetPneumatophoresRhizophora – breathing rootsgrow upward, lenticelsAdventitious storageSimple (sweet potato) | Fasciculated (Dahlia) | Moniliform (spinach) | Nodulose (Maranta)SupportProp (banyan) | Stilt (maize, sugarcane) | Climbing (betel) | Clinging (Ivy) | Plank | BuoyantSpecialEpiphytic (velamen; Vanda) | Haustoria (Cuscuta, Viscum)

In the figure : Storage tap roots, pneumatophores and a table of other modifications.

Rule 1 : Storage and respiration — Tap-root storage: fusiform (swollen in middle; radish), conical (broad base; carrot), napiform (spherical; beet). Adventitious storage (no fixed shape): simple tuberous (sweet potato), fasciculated (Dahlia, Asparagus), moniliform (spinach), nodulose (Curcuma amada, Maranta). Pneumatophores: breathing roots of mangroves, grow upward, bear lenticels.

  • Easy : Radish swells in the middle; carrot tapers down.
  • Medium : Pneumatophores are negatively geotropic (upward).
  • Exam-type (CET) : Napiform = beet.

Rule 2 : Support and special functions — Prop (banyan; pillar-like), stilt (maize, sugarcane, Pandanus), climbing (betel, pepper, money plant), clinging (Ivy), plank/buttress (silk cotton), buoyant (Jussiaea). Epiphytic roots: velamen absorbs air moisture (Vanda). Haustoria: parasites (Cuscuta = total; Viscum = partial).

  • Easy : Prop = from banyan branches; stilt = from lower nodes.
  • Medium : Cuscuta = leafless yellow total parasite.
  • Exam-type (CET) : Velamen absorbs moisture from air.
Remember

Radish = fusiform; carrot = conical; beet = napiform; banyan = prop.

Common mistake and CET trap

‘Sweet potato is a tap root’ is wrong (adventitious). Trap: ‘Cuscuta is a partial parasite’ is wrong (total).

Shortcut

Memory clue : "F-C-N: Fat-middle (radish), Cone (carrot), Nearly round (beet)".

Spot the difference

TypeExampleRole
FusiformRadishStorage
PneumatophoreRhizophoraRespiration
PropBanyanSupport
HaustoriaCuscutaAbsorption

Practice questions

Easy
  1. 1Example of fusiform root.
  2. 2Type of beet root?
  3. 3What are pneumatophores?
Medium
  1. 4Where are prop roots?
  2. 5Example of stilt root.
  3. 6Function of velamen?
Challenging
  1. 7Haustoria occur in?
  2. 8What is moniliform root?
Show answers (try them yourself first)
  1. 1Radish.
  2. 2Napiform.
  3. 3Breathing roots growing upward.
  4. 4From banyan branches.
  5. 5Maize, sugarcane, Pandanus.
  6. 6Absorbs moisture from air.
  7. 7Parasitic plants (Cuscuta, Viscum).
  8. 8Bead-like swollen root (spinach).

Stem and its modifications

From daily life

A potato grows underground so it looks like a root, but its ‘eyes’ are buds – so it is a stem.

Simple definition

Stem = part growing from the plumule, with nodes and internodes, bearing buds and leaves. Modifications: underground, sub-aerial and aerial.

Stem modificationsStem modifications: undergroundRhizomeginger, turmericStem tuberpotato (eyes)Bulbonion, garlicCormColocasia, yamSub-aerialTrailer, runner (Cynodon), stolon (Mentha), sucker(Chrysanthemum, banana), offset (Eichhornia, Pistia)Aerial modificationsThorn (Citrus) | Phylloclade (Opuntia) | Cladode (Asparagus)Cladophyll (Ruscus) | Tendril (grape, Passiflora) | Bulbil (Dioscorea)Sign of a stem: nodes + bud / scale leaf

In the figure : Four underground stems and sub-aerial/aerial modifications.

Rule 1 : Underground stems — Functions: food storage, perennation, vegetative propagation. Rhizome (horizontal; ginger, turmeric, lotus). Stem tuber (swollen tip; potato; ‘eyes’ = nodes). Bulb (reduced stem + fleshy leaves; onion = tunicated, garlic = scaly). Corm (vertical spherical; Colocasia, yam).

  • Easy : Potato is a stem because of nodes and buds.
  • Medium : Ginger = rhizome; onion = bulb.
  • Exam-type (CET) : Rhizome grows sympodially (ginger) or monopodially (lotus).

Rule 2 : Sub-aerial and aerial modifications — Sub-aerial: trailer (Euphorbia), runner (Cynodon), stolon (Mentha), sucker (Chrysanthemum, banana), offset (Eichhornia, Pistia). Aerial: thorn (from a bud; Citrus), phylloclade (green flat stem; Opuntia), cladode (one internode; Asparagus), cladophyll (Ruscus), tendril (grape), bulbil (Dioscorea).

  • Easy : Green part of Opuntia is the stem (leaves are spines).
  • Medium : Thorn reduces transpiration and protects.
  • Exam-type (CET) : Phylloclade is fleshy, with nodes.
Remember

Underground stems = R-T-B-C: Rhizome, Tuber, Bulb, Corm.

Common mistake and CET trap

‘Potato is a root’ is wrong. Trap: ‘Opuntia leaves are green’ is wrong (spines; the stem is green).

Shortcut

Memory clue : "Rhizome = Ride horizontally, Tuber = Tip swell, Bulb = Bunch of leaves, Corm = Chubby ball".

Spot the difference

TypeExampleClue
RhizomeGinger, turmericHorizontal, nodes
TuberPotatoEyes
BulbOnionFleshy leaves
CormColocasiaVertical, round

Practice questions

Easy
  1. 1Two features of a stem.
  2. 2Example of rhizome.
  3. 3What are the ‘eyes’ of potato?
Medium
  1. 4Which bulb is onion?
  2. 5What is a phylloclade?
  3. 6Example of runner.
Challenging
  1. 7Thorn develops from?
  2. 8Stem tuber vs root tuber.
Show answers (try them yourself first)
  1. 1Nodes and internodes; buds.
  2. 2Ginger, turmeric.
  3. 3Nodes with buds.
  4. 4Tunicated.
  5. 5Flat green leaf-like stem.
  6. 6Cynodon (grass).
  7. 7A bud.
  8. 8Stem tuber has eyes/nodes; root tuber does not.

The leaf

From daily life

The leaf is the plant's kitchen; the blade catches sunlight and the stalk holds it at the right place.

Simple definition

Leaf = a flat, green, limited-growth organ produced at a node. Three parts: leaf base (hypopodium), petiole (mesopodium), lamina (epipodium).

Leaf: parts and typesLeaf: partsLamina (epipodium)Petiole (mesopodium)Leaf base (hypopodium)Stipules: stipulate / exstipulateCompound leafPinnateon rachisPalmateat petiole tipParipinnate (Cassia) | Imparipinnate (Rosa)Bipinnate | Tripinnate (Moringa)Unifoliate (Citrus) ... Multifoliate (Bombax)PhyllotaxyAlternatemangoWhorledNeriumOpp. decussateCalotropisOpp. superposedjamun

In the figure : Parts of a leaf, simple/compound leaves and phyllotaxy.

Rule 1 : Parts and types — The axil bears a bud; no apical bud. With stipules = stipulate; without = exstipulate. With petiole = petiolate; without = sessile. Simple = entire blade; compound = leaflets: pinnate (on rachis: Cassia, Rosa) or palmate (at petiole tip). Dicot leaf is dorsiventral; monocot is isobilateral.

  • Easy : A leaflet has no axillary bud; a leaf does.
  • Medium : Rachis represents the midrib.
  • Exam-type (CET) : Venation = vein pattern (dicots reticulate; monocots parallel).

Rule 2 : Modifications and phyllotaxy — Leaf spines (Opuntia, Agave), leaf tendrils (Lathyrus, pea), hooks (Bignonia), phyllode (Acacia – flat leaf-like petiole). Phyllotaxy: alternate (mango), opposite (decussate – Calotropis; superposed – jamun), whorled (Nerium).

  • Easy : Alternate = one per node; whorled = many.
  • Medium : Phyllode = modified petiole (xerophytic).
  • Exam-type (CET) : Decussate = pairs at right angles.
Remember

Simple = entire; compound = leaflets; pinnate = feather-like; palmate = hand-like.

Common mistake and CET trap

‘Leaflet axil bears a bud’ is wrong. Trap: ‘phyllode = modified leaf blade’ is wrong (petiole).

Shortcut

Memory clue : "Pinnate = Pen feather; Palmate = Palm".

Spot the difference

PointPinnatePalmate
LeafletsOn rachisAt petiole tip
ExampleRosa, CassiaOxalis (tri)

Practice questions

Easy
  1. 1Three parts of a leaf.
  2. 2What is a sessile leaf?
  3. 3What is a stipule?
Medium
  1. 4Simple vs compound.
  2. 5Phyllode forms from?
  3. 6Example of alternate phyllotaxy.
Challenging
  1. 7Example of whorled.
  2. 8Why leaf tendril?
Show answers (try them yourself first)
  1. 1Leaf base, petiole, lamina.
  2. 2A leaf without petiole.
  3. 3Lateral outgrowth at the leaf base.
  4. 4Entire blade / divided into leaflets.
  5. 5Petiole (Acacia).
  6. 6Mango.
  7. 7Nerium.
  8. 8Support for climbing.

Inflorescence and flower

From daily life

On a stalk flowers open one after another; their arrangement follows a fixed pattern called inflorescence.

Simple definition

Inflorescence = a specialised axis bearing flowers. Racemose (unlimited growth) and cymose (limited). Flower = a modified shoot for sexual reproduction; four whorls on the thalamus.

Inflorescence and flowerRacemoseCymoseunlimited; old at baseAcropetal; centripetallimited; oldest at apexBasipetal; centrifugalInsertion (ovary)Hypogynoussuperior ovaryPerigynoussemi-superiorEpigynousinferior ovaryComplete = 4 whorls | Perfect = bisexualUnisexual | Neuter = neither (marigold ray floret)Monoecious (maize) | Dioecious (date palm, papaya)Zygomorphic (pea) – 1 plane | Actinomorphic (hibiscus) – any plane

In the figure : Racemose and cymose; insertion of ovary; flower terms.

Rule 1 : Racemose and cymose — Racemose: unlimited axis; apical bud keeps growing; older flowers at base; acropetal order; opening centripetal. Cymose: limited growth; axis ends in a flower; oldest flower at apex; basipetal; centrifugal. Advantage: flowers mature at different times, improving pollination.

  • Easy : Racemose = old at base; cymose = old at apex.
  • Medium : Acropetal = base to tip.
  • Exam-type (CET) : Cymose ends in a flower.

Rule 2 : Flower terms and insertion — Complete (four whorls), perfect (androecium + gynoecium), unisexual, neuter; monoecious (maize) / dioecious (date palm, papaya). Zygomorphic (pea) / actinomorphic (hibiscus). Insertion: hypogyny (superior ovary; brinjal), perigyny (cup; rose), epigyny (inferior ovary; sunflower, guava).

  • Easy : Hypo = others below; ovary on top.
  • Medium : Epi = others above; ovary below.
  • Exam-type (CET) : Zygomorphic has a single mirror plane.
Remember

Racemose keeps growing; cymose ends with a full stop.

Common mistake and CET trap

‘Cymose has a growing apical bud’ is wrong. Trap: ‘epigyny has a superior ovary’ is wrong.

Shortcut

Memory clue : "Hypo = Highest ovary; Epi = Embedded ovary".

Spot the difference

PointRacemoseCymose
GrowthUnlimitedLimited
Oldest flowerBaseApex
OrderAcropetalBasipetal

Practice questions

Easy
  1. 1What is inflorescence?
  2. 2Where is the oldest flower in racemose?
  3. 3Opening order in cymose?
Medium
  1. 4What is a perfect flower?
  2. 5Example of monoecious plant.
  3. 6Example of zygomorphic.
Challenging
  1. 7Example of hypogynous.
  2. 8Example of epigyny.
Show answers (try them yourself first)
  1. 1Specialised axis bearing flowers.
  2. 2At the base.
  3. 3Centrifugal (centre outward).
  4. 4Has both reproductive whorls.
  5. 5Maize.
  6. 6Pea.
  7. 7Brinjal, mustard, china rose.
  8. 8Sunflower, guava.

Floral whorls

From daily life

A flower is made of four rings: green protectors outside, coloured petals, then male parts, finally the female part in the centre.

Simple definition

Four whorls: calyx (K) sepals, corolla (C) petals, androecium (A) stamens, gynoecium (G) carpels. Perianth = tepals (calyx and corolla alike).

Floral whorls and placentationFlower (L.S.)Calyx (K) – sepalsCorolla (C) – petalsAndroecium (A) – stamensGynoecium (G) – carpelPlacentationMarginalpeaAxilehibiscusParietalpapayaBasalsunflowerFree centralDianthusAestivation: Valvate | Twisted | Imbricate | Vexillary (pea)Cohesion = same whorl fused | Adhesion = different whorls fusedSyncarpous = carpels fused | Apocarpous = free

In the figure : Section of a flower, five placentation types and terms.

Rule 1 : Calyx, corolla, perianth — Calyx: outermost; green sepals; protection; gamosepalous (fused) / polysepalous (free). Caducous, deciduous, persistent (brinjal). Corolla: petals; attracts pollinators; gamopetalous / polypetalous. Perianth: tepals; polyphyllous / gamophyllous. Aestivation: valvate, twisted, imbricate, vexillary (pea: standard, wings, keel). Epicalyx: Malvaceae (okra).

  • Easy : Gamo = fused; poly = free.
  • Medium : Vexillary = butterfly-shaped corolla of pea.
  • Exam-type (CET) : Aestivation = arrangement in the bud.

Rule 2 : Androecium, gynoecium, placentation — Stamen = anther (tetrasporangiate) + filament + connective. Cohesion = fusion within a whorl (adelphy; syngenesious); adhesion = fusion between whorls (epipetalous). Carpel = stigma + style + ovary; syncarpous / apocarpous. Placentation: marginal (pea), axile (china rose), parietal (papaya), basal (sunflower), free central (Dianthus).

  • Easy : Anther makes pollen (four locules).
  • Medium : Syncarpous = carpels fused.
  • Exam-type (CET) : Placenta = tissue bearing ovules.
Remember

K-C-A-G outside to inside; cohesion = within, adhesion = between whorls.

Common mistake and CET trap

‘Calyx is the inner whorl’ is wrong. Trap: ‘syncarpous = free carpels’ is wrong.

Shortcut

Memory clue : "K-C-A-G: ‘Kids Can Always Giggle’ (outside to inside)".

Spot the difference

WhorlPartsRole
CalyxSepalsProtection
CorollaPetalsAttraction
AndroeciumStamensPollen
GynoeciumCarpelsOvules

Practice questions

Easy
  1. 1Function of calyx?
  2. 2What is gamopetalous?
  3. 3What is perianth?
Medium
  1. 4Example of vexillary aestivation.
  2. 5Three parts of stamen.
  3. 6What is epipetalous?
Challenging
  1. 7Example of axile placentation.
  2. 8Syncarpous vs apocarpous.
Show answers (try them yourself first)
  1. 1Protects the bud.
  2. 2Petals fused.
  3. 3Whorl of tepals.
  4. 4Pea.
  5. 5Anther, filament, connective.
  6. 6Stamens attached to petals (adhesion).
  7. 7China rose, cotton.
  8. 8Fused / free carpels.

Fruit, seed and families

From daily life

A mango has soft pulp and a stone with the seed inside. A fruit is the ovary grown after fertilisation.

Simple definition

Fruit = ovary after fertilisation; seed = fertilised ovule. Pericarp = epicarp + mesocarp + endocarp. Families: Fabaceae (pea), Solanaceae (Datura).

Fruit, seed and familiesMango (drupe)Epicarp | MesocarpEndocarp (stone) + seedSeedTesta + Tegmen | HilumRadicle, plumule, cotyledonsSeed typesEndospermic: castorfood partly leftNon-endospermic: peafood used upEpicotyl | HypocotylFruit: simple (1 ovary) | aggregate (many ovaries, 1 flower)Composite (1 inflorescence): syconus (fig), sorosis (pineapple)False fruit (apple) | Parthenocarpy = fruit without fertilisationFabaceae (pea): K(5) C1+2+(2) A(9)+1 G1, legumeSolanaceae (Datura): K(5) C(5) A5 G(2), berry/capsuleFabaceae: marginal placentation | Solanaceae: axile

In the figure : Mango, seed structure, fruit types and formulas of two families.

Rule 1 : Fruit and seed — True fruit from ovary only (mango); false fruit from other parts too (apple); parthenocarpy = fruit without fertilisation (banana, seedless grape). Simple (one ovary): dry (achene, caryopsis, capsule, legume) or fleshy (berry – tomato, drupe – coconut). Aggregate (many ovaries, one flower), composite (one inflorescence; syconus, sorosis). Seed: seed coat (testa + tegmen), hilum, embryo (radicle, plumule, cotyledons); endospermic (castor) / non-endospermic (pea).

  • Easy : Mango is a drupe: stone = endocarp.
  • Medium : Parthenocarpic fruits are seedless.
  • Exam-type (CET) : Hilum = scar where seed attached.

Rule 2 : Fabaceae and Solanaceae — Fabaceae (pea): root nodules; pinnate alternate leaves; racemose; bisexual zygomorphic flower; 5 gamosepalous calyx; vexillary corolla; 10 diadelphous stamens (9+1); monocarpellary; marginal placentation; legume; non-endospermic. Solanaceae (Datura): tap root; simple alternate leaves; solitary; actinomorphic; calyx 5 valvate persistent; corolla 5 gamopetalous; 5 epipetalous stamens; bicarpellary syncarpous; axile; berry/capsule; endospermic.

  • Easy : Fabaceae: K(5) C1+2+(2) A(9)+1 G1.
  • Medium : Solanaceae: K(5) C(5) A5 G(2).
  • Exam-type (CET) : Pea = legume; Datura = capsule.
Remember

Fabaceae = legume + marginal; Solanaceae = berry/capsule + axile.

Common mistake and CET trap

‘Apple is a true fruit’ is wrong (false). Trap: ‘Datura has marginal placentation’ is wrong (axile).

Shortcut

Memory clue : "Pea = Pod (legume); Pericarp = E-M-E (epi, meso, endo)".

Spot the difference

PointFabaceaeSolanaceae
FlowerZygomorphicActinomorphic
PlacentationMarginalAxile
FruitLegumeBerry/capsule

Practice questions

Easy
  1. 1Three layers of pericarp.
  2. 2Example of false fruit.
  3. 3What is parthenocarpy?
Medium
  1. 4Legume belongs to?
  2. 5Example of sorosis.
  3. 6Example of endospermic seed.
Challenging
  1. 7What is hilum?
  2. 8Floral formula of Fabaceae.
Show answers (try them yourself first)
  1. 1Epicarp, mesocarp, endocarp.
  2. 2Apple.
  3. 3Fruit formation without fertilisation.
  4. 4Fabaceae.
  5. 5Pineapple.
  6. 6Castor.
  7. 7Scar where seed was attached.
  8. 8K(5) C1+2+(2) A(9)+1 G1.

Quick revision of the whole lesson

ConceptKey fact
RootCap, meristem, elongation, hair, maturation
Root modificationRadish fusiform; carrot conical; beet napiform
Stem modificationRhizome, tuber, bulb, corm
Leaf3 parts; simple/compound; phyllotaxy
InflorescenceRacemose unlimited; cymose limited
WhorlsK, C, A, G; five placentation types
Fruit / familiesTrue vs false; Fabaceae, Solanaceae

🎯 Most important points for the exam

  • Root structure and habitat groups.
  • Root and stem modifications (with examples).
  • Compound leaf and phyllotaxy.
  • Racemose vs cymose; insertion.
  • Aestivation, cohesion/adhesion, placentation.
  • Fruit types, seed, Fabaceae–Solanaceae.
Study mantra

Understand the concept → draw the figure → memorise the key points → solve questions yourself.