■ Plant Kingdom – Class 11 (Short Notes)
1. Classification Basis
Thallophyta → Bryophyta → Pteridophyta → Gymnosperms → Angiosperms (increasing
complexity)
Criteria: Thallus structure, vascular tissue, seed habit, flowers.
2. Algae (Thallophyta)
Features: Aquatic, chlorophyll, simple thallus, no roots/stem/leaves.
Types (based on pigments & storage product):
• Chlorophyceae (Green algae): Chlorophyll a, b; starch; e.g. Chlamydomonas, Spirogyra.
• Rhodophyceae (Red algae): Chlorophyll a, d; floridean starch; e.g. Polysiphonia.
• Phaeophyceae (Brown algae): Chlorophyll a, c; mannitol, laminarin; e.g. Laminaria, Fucus.
Reproduction: Vegetative (fragmentation), Asexual (zoospores), Sexual (isogamy → oogamy).
3. Bryophytes (Amphibians of Plant Kingdom)
No true roots/stem/leaves; no vascular tissue.
Life cycle: Gametophyte dominant.
Examples: Mosses (Funaria), Liverworts (Marchantia).
Reproduction: Archegonia (■), Antheridia (■).
4. Pteridophytes
First vascular cryptogams (have xylem & phloem).
Main plant body: Sporophyte.
Examples: Ferns (Dryopteris), Selaginella (heterosporous).
Leaves: Microphylls (small), Macrophylls (large).
Reproduction: Spores → Prothallus (gametophyte).
5. Gymnosperms
Naked seeds, no fruit.
Vascular tissue present.
Sporophyte dominant.
Examples: Pinus, Cycas.
Male cone (pollen), Female cone (ovules).
6. Angiosperms
Flowering plants.
Seed enclosed in fruit.
Vascular tissue well developed.
Divisions:
• Monocots (1 cotyledon, fibrous roots, parallel venation, e.g. Wheat, Rice).
• Dicots (2 cotyledons, tap root, reticulate venation, e.g. Pea, Mango).
7. Alternation of Generations
Haplo-diplontic: Both gametophyte & sporophyte phases alternate.
Seen in Bryophytes, Pteridophytes, Gymnosperms, Angiosperms.
1. Classification Basis
Thallophyta → Bryophyta → Pteridophyta → Gymnosperms → Angiosperms (increasing
complexity)
Criteria: Thallus structure, vascular tissue, seed habit, flowers.
2. Algae (Thallophyta)
Features: Aquatic, chlorophyll, simple thallus, no roots/stem/leaves.
Types (based on pigments & storage product):
• Chlorophyceae (Green algae): Chlorophyll a, b; starch; e.g. Chlamydomonas, Spirogyra.
• Rhodophyceae (Red algae): Chlorophyll a, d; floridean starch; e.g. Polysiphonia.
• Phaeophyceae (Brown algae): Chlorophyll a, c; mannitol, laminarin; e.g. Laminaria, Fucus.
Reproduction: Vegetative (fragmentation), Asexual (zoospores), Sexual (isogamy → oogamy).
3. Bryophytes (Amphibians of Plant Kingdom)
No true roots/stem/leaves; no vascular tissue.
Life cycle: Gametophyte dominant.
Examples: Mosses (Funaria), Liverworts (Marchantia).
Reproduction: Archegonia (■), Antheridia (■).
4. Pteridophytes
First vascular cryptogams (have xylem & phloem).
Main plant body: Sporophyte.
Examples: Ferns (Dryopteris), Selaginella (heterosporous).
Leaves: Microphylls (small), Macrophylls (large).
Reproduction: Spores → Prothallus (gametophyte).
5. Gymnosperms
Naked seeds, no fruit.
Vascular tissue present.
Sporophyte dominant.
Examples: Pinus, Cycas.
Male cone (pollen), Female cone (ovules).
6. Angiosperms
Flowering plants.
Seed enclosed in fruit.
Vascular tissue well developed.
Divisions:
• Monocots (1 cotyledon, fibrous roots, parallel venation, e.g. Wheat, Rice).
• Dicots (2 cotyledons, tap root, reticulate venation, e.g. Pea, Mango).
7. Alternation of Generations
Haplo-diplontic: Both gametophyte & sporophyte phases alternate.
Seen in Bryophytes, Pteridophytes, Gymnosperms, Angiosperms.
