Plant Kingdom

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Cytotaxonomy: It is based on cytological information like chromosome

number, structure, behaviour etc.

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Chemotaxonomy: It uses chemical constituents of plants.

ÅLGÅË (PHÝÇØLØGÝ)

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Algae are chlorophyll-bearing, simple, thalloid, autotrophic and largely

aquatic (both fresh water and marine) organisms.

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Found in moist stones, soil and wood.

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Some of them occur in association with fungi (lichen) and animals (e.g.,

on sloth bear).

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The form and size of algae is highly variable. The size ranges from the

microscopic unicellular forms like Chlamydomonas, to colonial forms

like Volvox and to filamentous forms like Ulothrix and spirogyra.

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A few of the marine forms such as kelps, form massive plant bodies.

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Vegetative reproduction: By fragmentation. Each fragment

develops into a thallus.

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Asexual reproduction: By the production of spores. E.g.

zoospores (most common). They are flagellated (motile) and

on germination gives rise to new plants.

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Sexual reproduction: Through fusion of two gametes. It may be:

 Isogamous: Fusion of gametes similar in size. They may be

flagellated (e.g. Chlamydomonas) or non flagellated (non

motile, e.g. Spirogyra).

 Anisogamous: Fusion of two gametes dissimilar in size. E.g.

Some species of Chlamydomonas.

 Oogamous: Fusion between one large, non motile (static)

female gamete and a smaller, motile male gamete. E.g.

Volvox, Fucus.

Spirogyra

Chlamydomonas