The central idea of biological evolution is that all life on earth shares a common ancestry and some similarities have evolved in other ways. These are called homologies and analogies. Homology refers to the traits inherited by two different organisms from a common ancestry. Organs such as bat’s wing, wings of birds, seal’s flipper, forelimb of a horse, and human arm are homologous organs. Plants too have homologous structures like those seen in animals. The leave of some plants like the pitcher, venus fly trap, poinsettia and cactus have homologous structure. Analogy refers to the similarity in function of two different organisms due to convergent evolution and not common ancestry. An example of an analogous trait would be the wings of insects, bats and birds. The leaves of opuntia and peepal are analogous organs in plants.
This video explains how identify and study the homologous and analogous organs in plants and animals.