"Ordines Anomali" of Bentham and Hooker includes

The system of classification of seed plants presented by Bentham and Hooker, represented the most well developed classification of natural system. The classification was published in 3 volumes of 'Genera plantarum'. The system divided phanerogams or seed plants into 3 classes dicotyledons, gymnospermae and monocotyledons. Dicotyledons were further subdivided into 3 subclasses - polypetalae, gamopetalae and monochlamydae based on the presence or absence of petals and their fusion. They were further divided into series, orders and families. No orders were recognised within monochlamydae and monocotyledons, the series being directly divided into families. But the system had a lot of demerits within it. He did not know the affinities of the families placed under 'Ordines anomate' and the families were tentativily grouped together. So, a few orders were not placed satisfactorily in the classification. Monochlamydae is an unnatural assemblage of taxa, which belongs elsewhere. The creation of this group has resulted in the separation of many closely related families.