Diversification in plant life appeared:

Diversification in plant life appeared due to long periods of evolutionary changes. Earlier, the plants were thalloid and there were no differentiation among root, stem and leaves. Vascular tissues were absent as in alglae and bryophytes. In pteridophytes, seed habit was observed for the first time. Gymnosperm consists of vascular tissue and naked seed habitat. Angiosperms showed secondary growth, along with fruit formation.