Plant Kingdom Class 11 | NEET Notes, Summary, and MCQs with Answers

By Botany Sir Himansu

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🌱 Introduction

The Plant Kingdom (Class 11 Biology, Chapter 3) is one of the most essential topics for NEET and CBSE exams.

It explains how plants evolved — from simple algae to complex flowering plants — and how they are classified based on structure, reproduction, and vascular tissues.

> Definition:

The Plant Kingdom includes all eukaryotic, multicellular, photosynthetic organisms with cell walls made of cellulose.

Let’s explore the journey of plants — from water to land — and understand their evolutionary hierarchy.

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🧭 Basis of Classification

Plants are classified into groups based on:

1️⃣ Plant body differentiation – Thallus / Root / Stem / Leaf

2️⃣ Vascular tissue presence – Xylem and Phloem

3️⃣ Seed formation – With or without seeds

4️⃣ Flower presence – Flowering (Angiosperms) or Non-flowering

👉 Mnemonic:

A → B → P → G → A

(Algae → Bryophyta → Pteridophyta → Gymnosperms → Angiosperms)

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🌊 ALGAE (Thallophyta)

> Simple, aquatic, autotrophic plants — the pioneers of plant life.

Feature Details

Habitat Mostly aquatic (freshwater/marine)

Body Thallus (no roots, stems, or leaves)

Vascular tissue Absent

Reproduction Vegetative (fragmentation), Asexual (zoospores), Sexual (isogamy, anisogamy, oogamy)

Reserve food Starch

Examples Chlamydomonas, Spirogyra, Ulva, Laminaria, Sargassum, Fucus

🔹 Classification of Algae

Type Pigment Reserve Food Example

Chlorophyceae (Green) Chlorophyll a, b Starch Spirogyra, Ulva

Phaeophyceae (Brown) Chlorophyll a, c; Fucoxanthin Mannitol, Laminarin Laminaria, Sargassum

Rhodophyceae (Red) Chlorophyll a, d; Phycoerythrin Floridean starch Gelidium, Polysiphonia

🌿 Economic Importance

Agar from red algae – used in labs.

Algin from brown algae – used in ice creams, jellies.

Chlorella – rich protein food source.

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🌿 BRYOPHYTES (Amphibians of the Plant Kingdom)

> Non-vascular land plants — depend on water for reproduction.

Feature Details

Body Thalloid or leafy; no true roots

Vascular tissue Absent

Habitat Moist, shady areas

Dominant generation Gametophyte

Reproduction Water required for fertilization

Sporophyte Dependent on gametophyte

Examples Riccia, Marchantia, Funaria, Polytrichum

🔹 Divisions of Bryophytes

Division Example Special Feature

Liverworts Riccia, Marchantia Thalloid body

Mosses Funaria, Polytrichum Leafy gametophyte

🧠 Moss life cycle clearly shows alternation of generations.

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🌾 PTERIDOPHYTES (First Vascular Land Plants)

> First true land plants — seedless but vascular.

Feature Details

Body Root, stem, and leaves well-differentiated

Vascular tissue Present (xylem & phloem)

Reproduction By spores (no seeds)

Dominant generation Sporophyte

Examples Selaginella, Lycopodium, Ferns, Equisetum

🌿 Economic Importance

Ornamental ferns

Soil binders

Equisetum rich in silica (medicinal use)

🧠 Selaginella = “Living fossil” → shows heterospory (microspores + megaspores).

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🌲 GYMNOSPERMS (Naked Seed Plants)

> Plants producing naked seeds not enclosed in fruits.

Feature Details

Plant body Roots, stems, leaves well-developed

Vascular tissue Present

Seeds Naked (no fruit covering)

Reproduction By unisexual cones (male & female)

Examples Cycas, Pinus, Ginkgo, Ephedra

🌿 Economic Importance

Timber – Pine, Cedar

Resin & Turpentine – industrial uses

Ephedrine – medicine from Ephedra

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🌸 ANGIOSPERMS (Flowering Plants)

> The most evolved group — seeds enclosed within fruits.

Feature Details

Plant body Roots, stems, leaves, flowers

Vascular tissue Well-developed

Seeds Enclosed within fruit

Reproduction Through flowers → pollination → double fertilization

Dominant generation Sporophyte

Examples Wheat, Mango, Pea, Rose

🔹 Subdivisions

Type Cotyledons Leaf Venation Root Type Flower Parts Example

Monocots 1 Parallel Fibrous 3’s multiples Wheat, Maize

Dicots 2 Reticulate Tap 4’s/5’s multiples Pea, Rose, Mango

🧠 Fruit = ripened ovary; Seed = fertilized ovule.

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🔁 ALTERNATION OF GENERATIONS

> Life cycle alternates between haploid gametophyte (n) and diploid sporophyte (2n).

Plant Group Dominant Generation

Algae Gametophyte

Bryophytes Gametophyte

Pteridophytes Sporophyte

Gymnosperms Sporophyte

Angiosperms Sporophyte

🧠 Evolution trend → Gametophyte dominance → Sporophyte dominance.

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📘 25 Important NEET/Board MCQs with Answers

# Question Answer

1 First plant group to evolve? Algae

2 Amphibians of plant kingdom? Bryophytes

3 First vascular plants? Pteridophytes

4 First seed plants? Gymnosperms

5 Most evolved plants? Angiosperms

6 Dominant phase in bryophytes? Gametophyte

7 Dominant phase in pteridophytes? Sporophyte

8 Bryophyte water need? Fertilization

9 Brown algae pigment? Fucoxanthin

10 Red algae pigment? Phycoerythrin

11 Living fossil? Selaginella

12 Gymnosperm example? Cycas

13 Angiosperm unique feature? Double fertilization

14 Vascular tissue first in? Pteridophytes

15 Monocot leaf venation? Parallel

16 Dicot root type? Tap root

17 Algae reserve food? Starch

18 Red algae reserve food? Floridean starch

19 Economic use of algae? Agar & Algin

20 Alternation of generations? Gametophyte ↔ Sporophyte

21 Bryophyte dominant phase? Gametophyte

22 Angiosperm pollination? Flowers

23 Seed enclosed in fruit? Angiosperms

24 Gymnosperm seed type? Naked

25 Pteridophyte reproduction? Spores