Question

information on plant classification

Answer 1

Plant taxonomy is the science that finds, identifies, describes, classifies, and names plants. Thus making it one of the main branches of taxonomy (the science that finds, describes, classifies, and names living things).

Plant taxonomy is closely allied to plant systematics, and there is no sharp boundary between the two. In practice, "Plant systematics" involves relationships between plants and their evolution, especially at the higher levels, whereas "plant taxonomy" deals with the actual handling of plant specimens. The precise relationship between taxonomy and systematics, however, has changed along with the goals and methods employed.

Plant taxonomy is well known for being turbulent, and traditionally not having any close agreement on circumscription and placement of taxa. See the list of systems of plant taxonomy.

Answer 2

Robert Whittaker (1959) proposed 5 kingdom system of classification for the study of living organisms. According to Whittaker the 5 kingdoms are:

1. Monera

2. Protista

3. Fungi

4. Plantae

5. Animalia

Let us study the divisions of Cryptogams in detail.

Cryptogams:

(plant which do not bear flower, fruit and seed)

1. Thallophyta

Habitat:

• grow mainly in water.

• Some are found in fresh water while some in saline/marine water

Structure:

• Do not have specific parts like root, stem, leaves, flowers.

• Autotrophic due to presence of chlorophyll.

• Unicellular or multicellular

• Microscopic or large

• Soft and fiber like body.

Other characteristics:

• Various types of fungi like yeasts and moulds which do not have chlorophyll are included.

Examples:

• Ulva

• Characteristics

• Spirogyra

• Ulothrix

• Sargassum

2. Bryophyta

Habitat:

• Amphibians: they grow in moist soil and need water for reproduction

Structure:

• Thalloid(presence of thallus), multicellular, autotrophic

• Flat, ribbon-like long, without true roots, stem and leaves.

• They have leaf-like parts and root like rhizoids.

• Do not have specific tissues for conduction of food and water.

Reproduction:

• Spore formation

Examples:

• Moss( Funaria)

• Marchantia

• Anthoceros

• Riccia

3. Pteridophyta

Structure:

• Well developed roots, stem and leaves

• Seperate tissues for the conduction of food and water.

• Do not bear flowers and fruits

• Well developed conducting system

Reproduction:

• With the helps of spores formed along the back or posterior surface of leaves.

• Asexually by spore formation

• Sexually by zygote formation.

Examples:

• Nephrolepis

• Marsilea

• Pteris

• Adiantum

• Equisetum

• Selaginella

• Lycopodium