The flowering plants of the plant kingdom

General features of flowering plants

Previously, all the flowering plants were kept in the sub-kingdom called Phanerogams.
They are the most developed and economically important plants.
All flowering plants bear seeds and are hence also known as spermatophytes.
These plants have distinct roots, stem, leaves and flowers.
The vascular system is also well developed in these plants.
Division Tracheophyta consists of three sub-divisions; Pteridophyta (a non-flowering division), and the two flowering divisions, Gymnospermae and Angiospermae.

Commonly known as conifers, they produce woody cones which are fruits made up of scales.
They bear seeds but without a seed coat. i.e. ovules are not enclosed within an ovary and the seed is naked.
They are distributed in the cold climates where snow, rather than rain, is the source of water.
They are mostly perennials, xerophytic, evergreen and tall woody plants.
They bear unisexual cones, i.e male and female cones are found in different branches of the same plant or different plants.
Pollination usually takes place with the help of wind.
The vascular bundles are conjoint, collateral and open.
The wood is usually soft and is widely used for lumber and timber.
e.g. Cycas, Pinus, Fir, Larch etc.

The most dominant ubiquitous flowering plants belong to this sub-division.
Flowers are well developed and bear ovules inside the ovary; hence the seeds are enclosed within the fruit.
The flower normally consists of four whorls; calyx (sepals), corolla (petals), androecium (stamens) and gynoecium (pistil).
Most of them are bisexual and few are unisexual.
Insects and animals usually act as pollinating agents as the petals are attractive.
They may be herbs, shrubs or trees.
e.g. peepal, orange, apple, maize, rice etc.

The sub-division Angiospermae is further divided into two classes; Monocotyledonae and Dicotyledonae.

Monocotyledonae:

These plants have only one seed leaf (cotyledon) in their seeds.
They have long and narrow leaves with parallel venation.
They have a fibrous or adventitious root system.
They are mainly herbs (stem is hollow, herbaceous and soft).
Nodes and internodes are present on stem and can be easily broken at these points.
Stem consists of open and scattered vascular bundles and lack vascular cambium.
The number of petals is either three (trimerous) or multiple of three.
e.g. rice, wheat, maize, onion, lily, Pistia, Lemna, sugarcane, bamboo etc.

Dicotyledonae:

These plants have two seed leaves (cotyledons) in their seeds.
The leaves are either simple or compound and are broad with net like reticulate venation.
They have tap root system with secondary roots.
They are ubiquitous and are herbs, shrubs or trees.
The stem is normally solid, hard and woody with no nodes and internodes.
Vascular bundles are closed and arranged in a ring.
The flower usually bears four or five petals or their multiples.
e.g. gram, pea, mustard, apple, mango, sunflower etc.

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