Plant kingdom is rich with a large number of species. At every stage of evolutionary development there are interesting examples of new structures coming up to give better tools of survival to the plant. The natural habitat of algae is water, so they can be compared to aquatic animals. As life started in the aquatic environment so algae are the most primitive group of plants. Moreover, their structure is simple with no special organs for special functions. The way amphibian animals are like a linking point between aquatic and terrestrial life, bryophytes show the same characteristic. Bryophytes need water to facilitate reproduction although they live on soil. In bryophytes we witness some development of leaf-like structures and root like structures. Antheridiopore and Archegoniopore can be compared to flowers of angiosperms. When we analyze Pteridophytes we can see development of vascular tissues for transport of substances. Pteridophytes show true roots as well. While the dominant phase is gametophyte in bryophytes it is sporophyte in Pteridophytes. This is another indication of evolution. Gymnosperm look more like a common plant, with well defined roots and stem. Appearance of seeds is another indicator of development. Seeds gave the ability to survive longer durations of adverse conditions. This is a sort of guarantee to continue progeny even after a long spell of adverse environmental conditions. Angiosperms are more advanced because of many factors. The seed is covered, which means more protection to the embryo. Appearance of flowers was a means to facilitate cross pollination for more variations. Angiosperms can modify almost any part for special purpose. For example, certain plants store excess food in modified leaves or stems or roots. This essay is an interesting description of how from simple thalloid algae plants have developed into more complicated angiosperms. While algae have a simple thallus to carry out all biological functions, angiosperms have dedicated tissue systems for various functions.