Phylogenetic system of classification - Taxonomy

Phylogenetic system of classification

The publication of the Origin of Species (1859) by Charles Darwin has given stimulus for the emergence of phylogenetic system of classification.

I Adolph Engler and Karl A Prantl system of classification

One of the earliest phylogenetic system of classification of the entire plant Kingdom was jointly proposed by two German botanists Adolph Engler ( 1844 - 1930) and Karl A Prantl (1849 - 1893). They published their classification in a monumental work “Die Naturelichen Pflanzen Familien” in 23 volumes (1887- 1915)

In this system of classification the plant kingdom was divided into 13 divisions. 

The first 11 divisions are Thallophytes, twelfth division is Embryophyta Asiphonogama (plants with embryos but no pollen tubes; Bryophytes and Pteridophytes) and the thirteenth division is Embryophyta Siphonogama (plants with embryos and pollen tubes) which includes seed plants.

II  Arthur Cronquist system of classification

Arthur Cronquist (1919 - 1992) an eminent American taxonomist proposed phylogenetic classification of flowering plants based on a wide range of taxonomic characters including anatomical and phytochemical characters of phylogenetic importance. 

He has presented his classification in 1968 in his book titled “The evolution and classification of flowering plants.” His classification is broadly based on the Principles of phylogeny that finds acceptance with major contemporary authors.

Cronquist classified the angiosperms into two main classes Magnoliopsida (=dicotyledons) and Liliopsida ( = monocotyledons). 

There are 6 subclasses, 64 orders, 320 families and about 165,000 species in Magnoliopsida, whereas in Liliopsida there are 5 sub classes, 19 orders, 66 families and about 50,000 species.

Cronquist system of classification also could not persist for a long time because, the system is not very useful for identification and cannot be adopted in herbaria due to its high phylogenetic nature.