Morphology of Flowering Plants

Story: Think Mango Tree = House. Root = Foundation underground — holds building strongly and sucks water like borewell pump. Stem = Pillars and walls — stands straight, carries water up and food down like lift in building. Leaf = Kitchen — cooks food using sunlight (photosynthesis). No kitchen, no food. Flower = Decoration for guests — colorful, scented to attract pollinators like bees like you decorate house for wedding to attract guests. Fruit = Roof / Tiffin Box — protects seeds inside like roof protects you, and later helps seeds travel. All angiosperms same house, just modifications for survival. Desert plants modify to save water, aquatic to float. Once you see house, you never forget body plan.

Two types: Tap system = One main road. Radicle from seed keeps growing as primary root like highway, then small colonies secondary and tertiary roots like lanes from highway. Seen in dicots — mustard, gram, mango, neem. Fibrous system = Many thin roads, no main highway. Radicle dies, many roots arise from base of stem like colony lanes. Seen in monocots — wheat, rice, onion, maize.

Now why modify? Because root is not only for absorption. Storage fridge: Carrot conical = ice-cream cone broad top narrow bottom. Radish fusiform = dhol middle fat. Turnip napiform = lota top ball. Sweet potato fasciculated cluster = fingers. All store food like fridge.
Support pillars: Banyan prop roots hanging like pillars holding heavy branches — you can sit under. Maize stilt roots extra legs from stem. Money plant climbing roots hands grabbing wall.
Breathing snorkels: In Sundarbans mangroves, mud has no oxygen. Roots come out of mud like snorkels called pneumatophores with small holes lenticels to breathe. Like you snorkel in water.
Nitrogen houses: Pea family makes small pink houses nodules for Rhizobium bacteria. Bacteria makes nitrogen food, plant gives house — friendship, symbiosis. That is why pulses increase soil fertility.

Stem always has nodes (joints) + internodes (between joints) + buds (eyes). Root never. So: Potato tuber you eat — eyes are nodes with buds, so stem — underground. Ginger rhizome horizontal fat like adrak, turmeric, with nodes. Onion bulb — disc stem with fleshy leaves like petticoat layers you remove, garlic same. Colocasia corm vertical fat like arbi.

Subaerial runners for spreading: Grass runner spreads on ground like electric wire, strawberry stolon, water hyacinth offset floats, banana sucker grows from base.

Aerial tricks: In gourd (lauki), axillary bud becomes spring-like hand tendril for climbing — you give it stick, it grabs and climbs. In Bougainvillea and Citrus, same bud becomes needle knife thorn for protection from goats — thorn is stem. In Opuntia desert cactus, stem becomes flat green chapati called phylloclade doing photosynthesis and kitchen work because leaves become spines to save water — spines are leaves! In Asparagus, same becomes thin needle cladode.
Once you see eyes = stem, you never confuse again.

Parts: Leaf base where attaches to stem, sometimes swollen pulvinus pillow in Gulmohar Gram to move leaf sleep at night, petiole stalk handle, lamina blade green plate, midrib central road, veins side roads, stipules small leafy outgrowths at base.

Venation = road pattern. Reticulate net-like like Delhi city roads criss-cross network seen in dicots mango peepal. Parallel like railway tracks parallel never meet seen in monocots banana wheat.

Simple vs Compound: Simple = one plate lamina cut but not to midrib still simple. Compound = fully cut into many leaflets like many plates. Pinnate neem leaflets on rachis like feather, Palmate silk cotton leaflets from one point like fingers of hand.

Phyllotaxy = arrangement smartly so own leaves don't shade each other for light. Alternate one leaf per node at different heights like people standing in lift alternate - china rose mustard sunflower. Opposite two leaves opposite each other at same node like guava Calotropis. Whorled many leaves at same node like Alstonia 5-8 leaves circle.

Modifications to survive: Pea upper leaflets become wire tendril for climbing. Cactus whole leaf becomes spine needle to save water. Australian Acacia petiole becomes flat phyllode leaf-like because leaf falls. Pitcher Nepenthes leaf becomes dabba pitcher with lid to eat insects for nitrogen because soil poor - insectivorous. Bladder Utricularia small bladders trap insects in water.

Peduncle = main axis bearing flowers.

Racemose indefinite = Main axis keeps growing never ending like principal speech never stops, new flowers come at top. Flowers open acropetal old down young up like old students sit front row, young back row queue - types: Raceme mustard stalked small stalk pedicel, Spike Achyranthes sessile no stalk, Spikelet wheat small spikes, Catkin hanging, Spadix Colocasia fleshy axis covered by big leaf bract spathe, Corymb flowers at same level despite different stalk lengths like people of different heights standing on steps to look equal, Umbel all from one point like umbrella ribs like onion.

Cymose definite = Main axis stops as flower like story ends, growth limited, flowers open basipetal old up young down reverse queue. Uniparous one branch helicoid spiral and scorpioid zigzag, biparous two branches, multiparous many.

Special: Cyathium Euphorbia looks like single flower but is cup of bracts with many male flowers + one female inside - fake single flower. Verticillaster Ocimum tulsi whorl at nodes two opposite cymose clusters like tulsi manjar. Hypanthodium fig peepal banyan fleshy receptacle becomes hollow ball with flowers inside - you eat inside-out cluster. Pollinated by wasp which enters through small hole ostiole - you eat wasp eggs with fig!

Thalamus = condensed shoot apex like compressed spring where all parts sit.

4 whorls: Outermost Calyx sepals green small guards protecting bud. Next Corolla petals colorful dress to attract bees. Then Androecium boys stamens - filament stalk + anther with pollen grains yellow dust. Innermost Gynoecium girls carpels - stigma top sticky, style tube, ovary base with ovules eggs.

Complete flower has all 4, incomplete missing one. Bisexual both boys girls same flower like rose, unisexual only one like papaya male female separate plants.

Symmetry: Actinomorphic radial any cut gives equal halves like round pizza, mustard, datura, chilli. Zygomorphic bilateral only one vertical cut equal like human face, pea, bean, gulmohar, cassia. Asymmetric no equal cut like Canna irregular.

Aestivation = how sepals/petals sit in bud before bloom like friends sitting. Valvate edges touch no overlap like friends shoulder touching. Twisted one edge overlaps next like China rose, ladyfinger, cotton. Imbricate irregular overlapping like Cassia, Gulmohar - one big one small. Vexillary flag 5 petals - 1 big standard flag, 2 wings side, 2 fused keel boat shape — you can remember flag of India.

Placentation = where ovules attach inside ovary seen in T.S. like seats in cinema. Marginal on one ridge suture like pea pod edge — single carpel. Axile central axis with many chambers like building with many rooms central pillar — China rose, lemon, tomato. Parietal periphery wall like ovules on wall — mustard, Argemone with false septum replum. Free central free central axis like Dianthus, Primrose. Basal single ovule at base like single bulb in room — sunflower, marigold. Superficial all over.

Ovary position: Hypogynous superior ovary top like mustard, China rose — thalamus flat. Perigynous half inferior rose, peach, plum thalamus cup. Epigynous inferior ovary below like guava, cucumber, ray florets sunflower — thalamus covers ovary.

Fruit wall pericarp 3 layers: Epicarp outer skin, mesocarp middle fleshy you eat, endocarp inner hard. True fruit only ovary mango. False fruit thalamus also becomes fleshy like apple strawberry — apple flesh is thalamus, not ovary!

Fleshy: Drupe mango coconut stony endocarp hard stone you cannot chew, Berry tomato brinjal many seeds soft, Hesperidium citrus leathery rind with juice hairs inside you eat hairs, Pome apple pear fleshy thalamus, Pepo cucumber, Balausta pomegranate, Amphisarca wood apple.
Dry dehiscent opens to release seeds: Legume pea opens both sutures, Follicle one suture, Siliqua mustard opens two sutures with replum false wall, Capsule many openings.
Indehiscent never opens: Achene, Caryopsis pericarp fused with testa wheat — you cannot separate skin and seed in wheat, Cypsela sunflower, Nut litchi, Samara wings for wind.
Aggregate many carpels one flower on fleshy thalamus strawberry many small fruits on one thalamus, rose many. Multiple composite whole inflorescence becomes one fruit jackfruit sorosis fleshy perianth spiky, fig syconus hollow receptacle. Parthenocarpic seedless banana without fertilization — no sex needed, develops automatically.
Seed: Dicot bean — hilum scar where attached to fruit, micropyle small pore water enters, testa outer seed coat, tegmen inner, cotyledons two thick food bags, embryonal axis radicle future root tip, plumule future shoot tip. Monocot maize — pericarp fused with testa cannot separate, aleurone protein layer, endosperm starchy food, scutellum single cotyledon shield, coleoptile cap covering plumule like helmet, coleorhiza cap covering radicle.

Fabaceae Papilionaceae pea pulse family — pulses you eat daily dal. Habit herb tree shrub, root nodulated with Rhizobium N2 fixation factories pink houses making nitrogen food, leaf pinnate pulvinate alternate, inflorescence racemose, flower zygomorphic papilionaceous bisexual, calyx 5 gamosepalous imbricate, corolla 5 papilionaceous vexillary 1 standard flag 2 wings 2 keel boat, androecium 10 diadelphous 9+1 nine friends together one separate, gynoecium 1 monocarpellary superior marginal placentation, fruit legume pod. Examples pea gram sem moong soybean — all pulses protein. Formula % K(5) C1+2+(2) A(9)+1 G1.

Solanaceae potato nightshade — vegetables you eat daily brinjal potato tomato chilli tobacco. Habit herb, stem aerial branched, leaf alternate simple exstipulate, inflorescence cymose, flower actinomorphic bisexual, calyx 5 gamosepalous persistent, corolla 5 gamopetalous twisted/valvate, androecium 5 epipetalous attached to petals, gynoecium bicarpellary syncarpous superior obliquely placed swollen placenta axile, fruit berry capsule. Formula Br or Ebr ⊕ K(5) C(5) A5 G(2).

Liliaceae lily — onion garlic you cry while cutting. Perennial herbs underground bulb corm rhizome, leaf alternate whorled, flower actinomorphic bisexual trimerous 3 parts, perianth 6 tepals 3+3 valvate petal sepal not distinct called tepals, androecium 6 3+3 epiphyllous attached to tepals, gynoecium tricarpellary syncarpous superior axile, fruit capsule rarely berry. Onion garlic tulip gloriosa aloe asparagus colchicine medicine. Formula Br ⊕ P(3+3) A3+3 G(3).
Difference trick: Fabaceae % zygomorphic flag diadelphous legume, Solanaceae ⊕ actinomorphic berry swollen placenta epipetalous, Liliaceae ⊕ trimerous perianth 6 tepals capsule.