Summary Note
Key concept recap
Introduction to Plant Kingdom
The plant kingdom (Plantae) encompasses algae, bryophytes, pteridophytes, gymnosperms, and angiosperms. Fungi and members of Monera and Protista having cell walls have been excluded from Plantae in modern classifications. The cyanobacteria, though once called blue-green algae, are no longer classified as algae.
Classification systems have evolved over time from artificial systems (based on superficial morphological characters like habit, colour, number and shape of leaves) to natural classification systems (based on natural affinities considering internal features like ultrastructure, anatomy, embryology, and phytochemistry) to the currently accepted phylogenetic classification systems based on evolutionary relationships. Modern tools such as Numerical Taxonomy, Cytotaxonomy, and Chemotaxonomy further assist in resolving classification difficulties.