Zygophyllales

Article By:

Chase, Mark W. Molecular Systematics Section, Jodrell Laboratory, Royal Botanical Gardens, Kew, Surrey, United Kingdom.

Last reviewed:June 2021

DOI:https://doi.org/10.1036/1097-8542.757623

An order of flowering plants in the eurosid I group of rosid eudicots. The plant order Zygophyllales comprises two small families of distant relationship (as evidenced by DNA sequence studies) to all other rosid eudicots: Krameriaceae and Zygophyllaceae (see illustration). In previous systems of plant classification, both families were placed in the order Polygalales or Sapindales because the two families—that is, Krameriaceae and Zygophyllaceae—have highly zygomorphic flowers (which are also features of members of the Polygalales or Sapindales). Members of the Krameriaceae (about 18 species) are photosynthetic parasitic plants ("hemiparasites") found from the southwestern United States to South America, whereas plants assigned to the Zygophyllaceae (approximately 280 species) are free-living and widely distributed in arid to semiarid zones throughout the warmer regions of the world. Some species of the latter family produce especially hard woods, such as lignumvitae (Bulnesia and Guaiacum), and a few other species produce medicinal compounds, such as the creosote bush (Larrea). See also: Flower; Lignumvitae; Magnoliophyta; Magnoliopsida; Polygalales; Rosidae; Sapindales

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