Plant Kingdom & Classification

• The Plant Kingdom is scientifically named Plantae and includes every plant from pond-scum to giant trees.
• Classification means sorting organisms into groups based on shared features for easy study and naming.
• Almost all plants are autotrophs – they make their own food by photosynthesis using sunlight.
• In binomial nomenclature each plant gets a genus + species name, e.g. mango = Mangifera indica.
• R. H. Whittaker (1969) proposed the Five Kingdom classification, in which plants form kingdom Plantae.
• Plant kingdom order, simplest to advanced: Algae → Bryophytes → Pteridophytes → Gymnosperms → Angiosperms.
• Carolus Linnaeus is the Father of Taxonomy; he gave the two-name (binomial) naming system.

The Plant Kingdom is scientifically named Plantae and includes every plant from pond-scum to giant trees.

Classification means sorting organisms into groups based on shared features for easy study and naming.

Almost all plants are autotrophs – they make their own food by photosynthesis using sunlight.

In binomial nomenclature each plant gets a genus + species name, e.g. mango = Mangifera indica.

R. H. Whittaker (1969) proposed the Five Kingdom classification, in which plants form kingdom Plantae.

Carolus Linnaeus is the Father of Taxonomy; he gave the two-name (binomial) naming system.

• Algae: simple, water-living, chlorophyll-bearing; body is a thallus with no true root, stem or leaf.
• Bryophytes (moss, Marchantia): the amphibians of plants – live on land but need water to reproduce.
• Pteridophytes (ferns): first plants with true roots, stem, leaves and a vascular system, but no seeds.
• Gymnosperms: seed plants with naked seeds not enclosed in a fruit (gymnos = naked, sperma = seed).
• Angiosperms: flowering plants with seeds enclosed in a fruit; largest and most advanced group.
• Algae — No — No seed, no flower
• Bryophytes — No — No seed, no flower
• Pteridophytes — Yes — No seed, no flower
• Gymnosperms — Yes — Naked seed, no flower
• Angiosperms — Yes — Seed in fruit, flowers

Algae: simple, water-living, chlorophyll-bearing; body is a thallus with no true root, stem or leaf.

Bryophytes (moss, Marchantia): the amphibians of plants – live on land but need water to reproduce.

Pteridophytes (ferns): first plants with true roots, stem, leaves and a vascular system, but no seeds.

Gymnosperms: seed plants with naked seeds not enclosed in a fruit (gymnos = naked, sperma = seed).

Angiosperms: flowering plants with seeds enclosed in a fruit; largest and most advanced group.

• Algae are classed by pigment colour into green, brown and red types.
• Chlorophyceae = green algae (Spirogyra); Phaeophyceae = brown algae (seaweeds).
• Rhodophyceae = red algae found in deeper sea water.
• Bryophytes cling to soil by thread-like rhizoids, which are not true roots.
• Their male organ is the antheridium and female organ is the flask-shaped archegonium.
• Sperm must swim through water to reach the egg, so bryophytes depend on moisture to reproduce.
• Chlorophyceae — Green — Spirogyra
• Phaeophyceae — Brown — Seaweeds
• Rhodophyceae — Red — Red algae

Algae are classed by pigment colour into green, brown and red types.

Chlorophyceae = green algae (Spirogyra); Phaeophyceae = brown algae (seaweeds).

Rhodophyceae = red algae found in deeper sea water.

Bryophytes cling to soil by thread-like rhizoids, which are not true roots.

Their male organ is the antheridium and female organ is the flask-shaped archegonium.

Sperm must swim through water to reach the egg, so bryophytes depend on moisture to reproduce.

• Gymnosperms bear naked seeds not enclosed inside any fruit.
• Common examples: Pine, Fir, Spruce, Cedar, Larch, Cypress, Cycas and the redwood Sequoia.
• Most are conifers – cone-bearing hill plants with needlelike leaves.
• Their needle leaves have small surface and thick cuticle to reduce water loss.
• Sequoia (redwood) is among the tallest and most massive plants on Earth.
• Pine, Fir, Spruce, Cedar, Larch and Cypress are famous timber-yielding conifers of India's hills.

Gymnosperms bear naked seeds not enclosed inside any fruit.

Most are conifers – cone-bearing hill plants with needlelike leaves.

Their needle leaves have small surface and thick cuticle to reduce water loss.

Sequoia (redwood) is among the tallest and most massive plants on Earth.

Pine, Fir, Spruce, Cedar, Larch and Cypress are famous timber-yielding conifers of India's hills.

• A cotyledon is the seed-leaf that stores and supplies food to the young sprouting plant.
• The number of cotyledons splits flowering plants into dicots and monocots.
• Dicots have two cotyledons (gram, pea, mango); a gram seed splits into two halves.
• Monocots have one cotyledon (wheat, maize, rice, onion); a wheat grain stays in one piece.
• Dicot floral parts are in fours or fives; monocot floral parts are in threes.
• Cotyledons — Two — One
• Leaf veins — Reticulate (net) — Parallel
• Root — Tap root — Fibrous
• Floral parts — 4 or 5 — 3

A cotyledon is the seed-leaf that stores and supplies food to the young sprouting plant.

The number of cotyledons splits flowering plants into dicots and monocots.

Dicots have two cotyledons (gram, pea, mango); a gram seed splits into two halves.

Monocots have one cotyledon (wheat, maize, rice, onion); a wheat grain stays in one piece.

Dicot floral parts are in fours or fives; monocot floral parts are in threes.

• Roots absorb water and minerals, anchor the plant firmly, and store reserve food.
• A tap root is one main thick root with branches (carrot, mustard), found in dicots.
• A fibrous root is a cluster of many thin equal roots (wheat, grass), found in monocots.
• Adventitious roots grow from places other than the radicle, e.g. banyan prop roots, maize stilt roots.
• Root hairs are fine outgrowths above the tip that actually absorb water and minerals.
• The root cap is a thimble-like cover that protects the tender root tip in hard soil.
• Tap root — Dicots — Carrot, mustard
• Fibrous root — Monocots — Wheat, grass
• Adventitious — Special cases — Banyan, maize

Roots absorb water and minerals, anchor the plant firmly, and store reserve food.

A tap root is one main thick root with branches (carrot, mustard), found in dicots.

A fibrous root is a cluster of many thin equal roots (wheat, grass), found in monocots.

Adventitious roots grow from places other than the radicle, e.g. banyan prop roots, maize stilt roots.

Root hairs are fine outgrowths above the tip that actually absorb water and minerals.

The root cap is a thimble-like cover that protects the tender root tip in hard soil.

• The stem is the upright (ascending) part that bears leaves, flowers and fruits; it grows from the plumule.
• Its main jobs are to hold up the plant and conduct water and food.
• A node is the point where a leaf attaches; the internode is the gap between two nodes.
• A bud is a tiny compressed, undeveloped (embryonic) shoot that can grow into a branch or flower.
• A terminal bud sits at the stem tip; an axillary bud sits in the leaf axil (armpit).
• Nodes, internodes and buds distinguish a stem from a root; potato and ginger are modified stems.

The stem is the upright (ascending) part that bears leaves, flowers and fruits; it grows from the plumule.

Its main jobs are to hold up the plant and conduct water and food.

A node is the point where a leaf attaches; the internode is the gap between two nodes.

A bud is a tiny compressed, undeveloped (embryonic) shoot that can grow into a branch or flower.

A terminal bud sits at the stem tip; an axillary bud sits in the leaf axil (armpit).

Nodes, internodes and buds distinguish a stem from a root; potato and ginger are modified stems.

• The leaf is a flat green lateral outgrowth of the stem and the main site of photosynthesis.
• Three parts of a typical leaf: the leaf base, petiole (stalk) and lamina (blade).
• The petiole holds the blade in light and lets it flutter, cooling it and supplying fresh air.
• The lamina is the broad green blade carrying veins, where most food-making happens.
• The central prominent main vein of the lamina is the midrib.
• Venation is the arrangement of veins – reticulate in dicots, parallel in monocots.

The leaf is a flat green lateral outgrowth of the stem and the main site of photosynthesis.

The petiole holds the blade in light and lets it flutter, cooling it and supplying fresh air.

The lamina is the broad green blade carrying veins, where most food-making happens.

The central prominent main vein of the lamina is the midrib.

Venation is the arrangement of veins – reticulate in dicots, parallel in monocots.

• A true fruit develops only from the ovary after fertilisation (mango, tomato).
• A false fruit develops from a part other than the ovary, like the thalamus – apple, pear, cashew.
• Clove is a spice obtained from the dried flower bud of the clove plant.
• Quinine, an anti-malarial drug, is obtained from the bark of the Cinchona plant.
• Tapa cloth is made from the bark of plants of the mulberry family (Moraceae).
• Plants give us food, fodder, fuel, fibre and medicine from various parts.
• Clove — Clove tree — Flower bud
• Quinine — Cinchona — Bark
• Saffron — Crocus — Stigma
• Tapa cloth — Mulberry (Moraceae) — Bark

A true fruit develops only from the ovary after fertilisation (mango, tomato).

A false fruit develops from a part other than the ovary, like the thalamus – apple, pear, cashew.

Clove is a spice obtained from the dried flower bud of the clove plant.

Quinine, an anti-malarial drug, is obtained from the bark of the Cinchona plant.

Tapa cloth is made from the bark of plants of the mulberry family (Moraceae).

• Fungi lack chlorophyll, so they cannot make their own food and are heterotrophic.
• Fungi reproduce by spore formation, as do bacteria, algae, ferns and mosses.
• A lichen is a symbiosis of a chlorophyll-containing alga with a fungus.
• In a lichen the alga makes food while the fungus gives shelter, water and minerals.
• Lichens are sensitive indicators of air pollution and do not grow in polluted air.
• Carl Linnaeus / vascular tissue: A. W. Eichler and others used vascular tissue features to classify plants.

Fungi lack chlorophyll, so they cannot make their own food and are heterotrophic.

Fungi reproduce by spore formation, as do bacteria, algae, ferns and mosses.

A lichen is a symbiosis of a chlorophyll-containing alga with a fungus.

In a lichen the alga makes food while the fungus gives shelter, water and minerals.

Lichens are sensitive indicators of air pollution and do not grow in polluted air.

Carl Linnaeus / vascular tissue: A. W. Eichler and others used vascular tissue features to classify plants.

• Insectivorous plants trap and digest insects to get nitrogen from nitrogen-poor soils.
• Examples include Pitcher plant (Nepenthes), Venus flytrap, Drosera (sundew) and Utricularia.
• The pitcher plant has a modified leaf shaped like a jug to trap insects.
• These plants are still green and photosynthetic – they only supplement nitrogen by eating insects.
• Parasitic plants like Cuscuta (dodder) take food from a host plant instead.
• Such traps are examples of leaf modification for special functions.

Insectivorous plants trap and digest insects to get nitrogen from nitrogen-poor soils.

The pitcher plant has a modified leaf shaped like a jug to trap insects.

These plants are still green and photosynthetic – they only supplement nitrogen by eating insects.

Parasitic plants like Cuscuta (dodder) take food from a host plant instead.

Such traps are examples of leaf modification for special functions.