PLANT DIVERSITY OF INDIA

CLASSIFICATION OF PLANTS
Herbs:
• Soft, green, tender stems; height below 1 meter.
Shrubs:
• Woody, perennial, bushy plants; branches arise near the base.
Trees:
• Large, woody perennials with a single main stem and a defined crown.

Parasites:
• Plants deriving nutrition from a living host using haustoria.
Epiphytes:
• Grow on host plants only for support; obtain no nutrition from host.
Climbers:
• Use tendrils, hooks or aerial roots to climb and access sunlight.

EFFECT OF ABIOTIC FACTORS ON PLANTS
Light:
• High intensity → root growth, short stems, thick leaves, more transpiration.
• Low intensity → reduced growth, flowering and fruiting.

Frost:
• Causes death of young plants; forms cankers and damages cells.

Snow:
• Acts as an insulating blanket; protects seedlings from extreme cold.

Temperature:
• High temperature → protein coagulation, tissue desiccation, plant death.

Die Back:
• Tip portions die gradually while roots remain alive.
• Common in Sal, Red Sanders; caused by frost, drought, grazing, dense canopy.

INSECTIVOROUS (CARNIVOROUS) PLANTS
Features:
• Grow in nutrient-poor soils (e.g., swamps).
• Possess chlorophyll; perform photosynthesis.
• Derive nutrients by trapping insects/animals.

Types:
Active – Movement-based traps (e.g., Venus Fly Trap).
Passive – Pitfall traps (e.g., Nepenthes).

Threats:
• Habitat loss, medicinal exploitation, pollution.

Important Species:
Nepenthes khasiana:
• Pitcher plant; endemic to Meghalaya.
Drosera:
• Sundew; sticky tentacles trap insects; found in nutrient-poor marshy soils.
Pinguicula:
• Butterwort; absent in India.
Utricularia:
• Bladderworts; over 200 species; aquatic traps.
Aldrovanda:
• Rootless aquatic plant; found in Sunderbans.
Genlisea:
• Corkscrew plant; traps with inward hairs.

INVASIVE PLANT SPECIES OF INDIA
Prosopis juliflora (Angreji Babool):
• Highly water-consuming; threatens native flora; major issue in Kutch.
Black Mimosa:
• Forms dense thickets; widespread in wet areas.
Carrot Grass (Parthenium / Congress grass):
• Releases chemicals that suppress crops; affects livestock.
Lantana camara:
• Outcompetes native species; widespread across India.
Siam Weed:
• Rapid spread in Kerala; native to South America.
Senna spectabilis:
• Threat to wildlife habitat in Nilgiri Biosphere Reserve.
Needle Bush:
• Thrives in dry scrub forests.
Black Wattle:
• Introduced in Western Ghats; regenerates rapidly post-fire.
Goat Weed:
• Aggressive colonizer across India.
Prickly Poppy:
• Found along forest fringes.
Water Hyacinth:
• Extremely invasive in lakes; blocks light and reduces oxygen.

IMPORTANT MEDICINAL PLANTS
Blue Vanda:
• Found in NE India; used ornamentally.
Ladies Slipper Orchid:
• Used for treating anxiety and muscle pain.
Sarpa Gandha (Rauvolfia serpentina):
• Treats hypertension, mental disorders, cholera; leaf juice used for eye problems.
Cycads:
• Gymnosperms; “living fossils”; found in Western Ghats, Northeast, Andamans.

PARTS OF A TREE
Roots:
• Anchoring, water absorption, nutrient uptake, vegetative reproduction.

Crown:
• Upper leafy portion; absorbs sunlight; removes excess water.

Leaves:
• Food production (photosynthesis).

Branches:
• Support leaves; conduct nutrients; store sugars.

Trunk:
• Structural support; transports water/nutrients.

Annual Rings:
• Indicate tree age (dendrochronology).

Bark:
• Protective layer; carries sap; source of latex, cinnamon.

ROOT TYPES
Taproot:
• Main descending root.
Lateral roots:
• Spread horizontally for support.
Buttresses:
• Vertical flanges aiding stability.
Prop roots:
• From branches; become supportive pillars (e.g., Banyan).
Stilt roots:
• From stem above ground (e.g., mangroves).
Pneumatophores:
• Aerial breathing roots of mangroves (e.g., Heritiera).
Haustorial roots:
• Parasitic roots (e.g., mistletoe).
Storage roots:
• Store starch; include tuberous roots.

IMPORTANT PARASITIC PLANTS OF INDIA
Gleadovia konyakianorum:
• Holoparasite from Nagaland; lacks chlorophyll.

Broomrape:
• Affects tobacco, tomato, eggplant; completely lacks chlorophyll.

Sapria Himalayana:
• Rare holoparasite from Arunachal Pradesh & Meghalaya.

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Subject: Environment

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