Phylogenetic System

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Phylogenetic System is a system of biological classification. It is based on evolutionary sequence and genetic relationships among the organisms. Darwin's book "On the Origin of Species by Means of Natural Selection" or "The Preservation of Races in the Struggle of Life" (1859) provided support for Taxonomy. The most important change was the change of the status of specied from fixity (ie static nature) to a dynamic or an everchanging one, which became dominant after Darwin. The classification of plants were on the basis of evolutionary development as well as morphological characters.

Adolf Engler (1844 - 1930) and Karl A. E. Prantl (1849 - 1893) published this system in their monograph Die Natürlichen Pflanzenfamilien. In it, they arranged the families and orders of flowering plants on the basis of complexity of floral morphology. Characters like a perianth with one whorl, unisexual flowers and pollination by wind were considered primitive as compared to perianth with two whorls, bisexual flowers and pollination by insects.

The plant kingdom is further divided into divisions, sub-divisions, classes, orders and families. According to this system, monocotyledons are considered more primitive than dicotyledons. It also considers evolution of angiosperms from a single source and the sequence of orders and families show parallel evolution.