System of A. P. de Candolle (1819).

Robert Brown published in 1827 his discovery of the gymnospermy of the ovules of the Coniferæ and Cycadeæ, and showed that the Gymnosperms, which had previously been classed with the Dicotyledons, must be regarded as an independent group.


System of Stephen Endlicher (1836–40).


System of A. Brongniart (1843).