CLASSIFICATION OF PLANTS

BIOLOGY SSS 2 FIRST TERM

WEEK ONE

CLASSIFICATION OF PLANTS

PERFORMANCE OBJECTIVE

Students should be able to;

1. Classify plants using
   1. Botanical
   2. Agricultural techniques of classification
   3. Classify plants based on life cycle

CONTENT

 The Classification Of Plants

All living organisms in the ecosystem are classified into kingdoms and sub-kingdoms based on their characteristics. Similarly, plants are also classified into different sub-kingdoms based on certain characteristic features.

The general classification of plants is made on certain criteria such as:

• Botanical type
• Geographical or ecological communities
• Classification based on Life Cycle

 

Plant species can be classified based on their life cycle.

1. Annuals

These are plants that complete their life cycle during a single season. They are normally herbaceous. Examples like corn, rice, wheat, and pulses are annuals plant.

 

2. Biennials

These are plants that require two years to complete their life cycle. They are normally herbaceous. For example, carrot, cabbage, onions, and beetroot are biennials plant.

3. Perennials

These are plants that have a long lifespan – typically more than two years. They are characteristically woody or herbaceous. Rose, lavender, dianthus, and lilies are prominent examples of perennials.

 

Taxonomic Classification Of Plants

Taxonomy is a system for classifying plants based on their genetic and evolutionary relationship. Plant Taxonomy is a branch of science that continues to change as new species are being found almost every day.

Plants are classified into a separate kingdom called the Kingdom Plantae. This current system of classification of plants is based on the evolutionary relationship amid other plants.

 

1. Coniferophyta (Gymnosperms)

It is a group of plants which is primarily evergreen and are native to the temperate zone. There are about 700 species discovered to date. They are vascular, non-flowering plants which produce seeds without the production of flower and fruits. Some common examples of gymnosperm include pines, cycads, cedars, etc.

 

2. Anthophyta (Angiosperms)

They can grow into big trees as well as small shrubs, bushes and herbs. The angiosperms are distributed all over the world (>250,000 species). Most of the plants that we see around us are grouped under this division.

Angiosperms are characterised by the seeds that are fully enclosed in fruits. They are subdivided into- Monocotyledonous and Dicotyledonous. Some common examples of angiosperms include mango trees, roses, jasmine, marry gold, etc.

3. Monocotyledons

Monocotyledonous plants are commonly referred to as monocot plants. They are flowering plants with seed containing one cotyledon. The venation pattern of their leaves is parallel-veined. Some common examples of monocot plants are rice, corn, sugarcane, tulips, onion, etc. There are around 50,000 species of monocotyledonous plants discovered to date.

4. Dicotyledons

Dicotyledonous plants are commonly referred to as dicot plants. They are flowering plants, mostly grown as herbs, shrubs, and trees with the seed containing two cotyledons. The venation pattern of their leaves radiates from a central main vein. Some common examples are figs, eucalyptus, potato, tomato, hibiscus, etc. There are around 200,000 species of dicotyledonous or dicots plants.

 

Agricultural Classification Of Plants

Agricultural classification of plants is the type of classification based on the uses of plants. In this classification, crops or plants are grouped into the following categories based on their uses.

 

1. Cereal Plants: These plants belong to the grass family and they provide carbohydrate, e.g. Maize, rice, millet, guinea corn, wheat, barley, oats etc.

 

2. Pulses (grain legumes): Pulses are crops which provides proteins for a man and animals when eaten. E.g. Cowpea, soyabeans, groundnut, lima bean, pigeon pea.

 

3. Roots and tuber crops: These crops produce tubers under the ground and they provide carbohydrate to human and animals when eaten, e.g. Cassava, yam, cocoyam, sweet potato, Irish potato, beets, carrot etc.

 

4. Vegetable crops: Vegetable crops provide vitamins and minerals to human and animals when consumed, e.g. tomatoes, amaranthus, onion, okra, cauliflower, spinach, bitter leaf, water leaves etc.

 

5. Fruit plants: Fruit plants also provide vitamins and minerals to human and animals when consumed, e.g. orange, banana, pineapple, mango, pawpaw, cashew etc.

 

6. Beverage plants: These crop plants provide food drinks when processed into finished products like bournvita, ovaltine, pronto etc. Examples of beverage crops are cocoa, coffee, tea, kola etc.

 

7. Spices: These crop plants provide vitamins and minerals to man and animals when consumed, e.g. Ginger, pepper, onion etc.

 

8. Oil plants: Oil plants can provide oil when processed both for domestic and industrial uses, e.g. Oil palm, groundnut, melon, coconut, soyabean, cotton etc.

 

9. Fibre crops: These are crop plants used for making clothing materials, ropes and bags, e.g. Cotton, sisal, hemp, kenaf, hibiscus etc.

 

10. Latex crops: These are crops which provide some white, sticky liquid (latex) used in plastic industries, e.g. rubber.

 

Importance of Plant Classification

The main purpose of classifying plants is to ensure that the right plants are correctly named, grouped and identified.

Plants are classified based on these 3 characteristics:

• The evergreen plants are plants that retain leaves at all times (all year round).
• Woody plants can also be grouped as deciduous or evergreen.
• Deciduous plants are seasonal plants which shed its leaves at the end of the growing season, either during the winter season in the temperate climate or during the dry season in the tropical climate.