- Plant kingdom is divided into Algae, Bryophytes, Pteridophytes, Gymnosperms, and Angiosperms.
- Artificial system of classification used gross superficial morphological characters and were based mainly on vegetative characters or on the androecium structure.
- Natural classification systems were based on natural affinities among the organisms and consider not only the external features, but also internal features.
- Phylogenetic classification systems are based on evolutionary relationships between various organisms which assumes that organisms belonging to the same taxa have a common ancestor.
- Numerical Taxonomy is based on all observable characteristics, where number and codes are assigned to all the characters and the data are then processed.
- Cytotaxonomy that is based on cytological information like chromosome number, structure, behavior.
- Chemotaxonomy is based on the chemical constituents of the plant.
Fig. algae, bryophytes, pteridophytes, gymnosperms, angiosperms