''Peganum'' L. is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

under the recently separated family

Nitrariaceae Nitrariaceae is a family of flowering plants in the order Sapindales. It comprises four genera, '' Malacocarpus'', '' Nitraria'', '' Peganum'' and '' Tetradiclis'', totalling 19 species. The family's main range is in the arid and semi-arid regio ...

. Formerly it used to be included in the family

Zygophyllaceae Zygophyllaceae is a family of flowering plants that contains the bean-caper and caltrop. The family includes around 285 species in 22 genera. Plants in the family Zygophyllaceae may be trees, shrubs, or herbs. They are often found in dry habit ...

Phylogeny and Species

The genus has around five species, occurring in warm temperate to subtropical regions across the world: * ''

Peganum harmala ''Peganum harmala'', commonly called wild rue, Syrian rue, African rue, esfand or espand,Mahmoud OmidsalaEsfand: a common weed found in Persia, Central Asia, and the adjacent areasEncyclopædia Iranica Vol. VIII, Fasc. 6, pp. 583–584. Origina ...

'' L. (

Harmal ''Peganum harmala'', commonly called wild rue, Syrian rue, African rue, esfand or espand,Mahmoud OmidsalaEsfand: a common weed found in Persia, Central Asia, and the adjacent areasEncyclopædia Iranica Vol. VIII, Fasc. 6, pp. 583–584. Origina ...

or Syrian rue) — Mediterranean region east to China * '' Peganum mexicanum'' Gray — Mexico * '' Peganum multisectum'' (Maxim.) Bobrov — China, Mongolia * '' Peganum nigellastrum'' Bunge — China * '' Peganum texanum'' M.E.Jones — southern North America Phylogenetic data suggests the following relationships:

References

Nitrariaceae {{Sapindales-stub