Plant Kingdom or Animal and Plant Kingdom
The whole plant kingdom is classified into two major divisions:
- Cryptogams (non-flowering plants) and
- Phanerogams (flowering plants).
The flowering plants are evolutionary more advanced than non-flowering plants.
1. Cryptogams
Cryptogams are divided into three subdivisions depending on the presence of roots, stems and leaf-like structures as under:
1.1 Thallophyta: In this group the plant body is not differentiated into roots, stems and leaves and the simple body is known as a thallus, e.g. algae, bacteria, fungi and lichens.
1.2 Bryophyta: Plants in this subdivision have body with stem and leaf-like structures but no roots, e.g. mosses.
1.3 Pteridophyta: Their body is differentiated into roots, stems and leaves, but they do not flower, e.g. ferns.
2. Phanerogams
Phanerogams include all the flowering plants of this earth. It is divided into two subdivisions: gymnosperms and angiosperms, on the basis of presence or absence of fruits.
2.1 Gymnosperms
Gymnosperms are those which have roots, stems, leaves, flowers and naked seeds. Their seeds are not enclosed within the fruit, e.g. pine, cycas, etc.
2.2 Angiosperm
Angiosperm plants have roots, stems, leaves, flowers and fruits. Their seeds are found within the fruit. Angiosperms are again divided into two classes:
2.2.1 Monocotyledonous plants are those which have only one cotyledon in their seeds, e.g. rice wheat, banana, coconut etc. In such plants, the leaves have parallel venation and fibrous root system.
2.2.2 In dicotyledonous plants the seeds have two cotyledons and the leaves have a network of veins (reticulate venation) e.g. mango, pea, gourd, sunflower etc.