Work on the lines suggested by the Linnaean fragmenta was continued in France by Bernard de Jussieu and his nephew, Antoine Laurent, and the arrangement suggested by the latter in his Genera Plantarum secundum Ordines Naturales disposita (1789) is the first which can claim to be a natural system.  The orders are carefully characterized, and those of Angiosperms are grouped in fourteen classes under the two main divisions Monocotyledons and Dicotyledons.  The former comprise three classes, which are distinguished by the relative position of the stamens and ovary; the eleven classes of the latter are based on the same set of characters and fall into the larger subdivisions Apetalae, Monopetalae and Polypetalae, characterized respectively by absence, union or freedom of the petals, and a subdivision, Diclines Irregulares, a very unnatural group, including one class only.  A.P. de Candolle introduced several improvements into the system.  In his arrangement the last subdivision disappears, and the Dicotyledons fall into two groups, a larger containing those in which both calyx and corolla are present in the flower, and a smaller, Monochlamydeae, representing the Apetalae and Diclines Irregulares of Jussieu.  The dichlamydeous group is subdivided into three, Thalamiflorae, Calyciflorae and Corolliflorae, depending on the position and union of the petals.  This, which we may distinguish as the French system, finds its most perfect expression in the classic Genera Plantarum (1862-1883) of Bentham and Hooker, a work containing a description, based on careful examination of specimens, of all known genera of flowering plants.  The subdivision is as follows:—­

  DICOTYLEDONS.

  Polypetalae: 
  Thalamiflorae. 
  Disciflorae. 
  Calyciflorae.

  Gamopetalae: 
  Inferae. 
  Heteromerae. 
  Bicarpellatae.

  Monochlamydeae in eight series. 
  Monocotyledons in seven series.

Of the Polypetalae, series 1, Thalamiflorae, is characterized by hypogynous petals and stamens, and contains 34 orders distributed in 6 larger groups or cohorts.  Series 2, Disciflorae, takes its name from a development of the floral axis which forms a ring or cushion at the base of the ovary or is broken up into glands; the ovary is superior.  It contains 23 orders in 4 cohorts.  Series 3, Calyciflorae, has petals and stamens perigynous, or sometimes superior.  It contains 27 orders in 5 cohorts.

Of the Gamopetalae, series 1, Inferae, has an interior ovary and stamens usually as many as the corolla-lobes.  It contains 9 orders in 3 cohorts.  Series 2, Heteromerae, has generally a superior ovary, stamens as many as the corolla-lobes or more, and more than two carpels.  It contains 12 orders in 3 cohorts.  Series 3, Bicarpellatae, has generally a superior ovary and usually two carpels.  It contains 24 orders in 4 cohorts.

The eight series of Monochlamydeae, containing 36 orders, form groups characterized mainly by differences in the ovary and ovules, and are now recognized as of unequal value.