Piperales is an order of flowering plants (4,170 recognized species). It necessarily includes the family Piperaceae but other taxa have been included or disincluded variously over time. Well-known plants which may be included in this order include black pepper, kava, the many Peperomias, pepper elder, lizard's tail, birthwort, and wild ginger.[1] The two perianthless families Piperaceae and Saururaceae are mainly herbaceous plants possessing highly reduced flowers.[2] [3]
In the APG IV system, of 2016, this order is placed in the clade magnoliids and is circumscribed as follows:
family Aristolochiaceae (including Asaraceae, Hydnoraceae and Lactoridaceae)
family Piperaceae
family Saururaceae
This is an expansion from the APG system, of 1998, which used the same placement (in the magnoliids) but used this circumscription:
family Aristolochiaceae
family Lactoridaceae
family Piperaceae
family Saururaceae
The Cronquist system, of 1981, placed the order in the subclass Magnoliidae of class Magnoliopsida [=dicotyledons] and used this circumscription:
family Chloranthaceae
family Piperaceae
family Saururaceae
The Engler system, in its update of 1964, placed the order in subclassis Archichlamydeae in class Dicotyledoneae [=dicotyledons] and used this circumscription:
family Chloranthaceae
family Lactoridaceae
family Piperaceae
family Saururaceae
The Wettstein system, latest version published in 1935, assigned the order to the Monochlamydeae in subclass Choripetalae of class Dicotyledones. It used the circumscription:
family Piperaceae