Taxonomy
The botanist Thomas Nuttall said he named the genus Wisteria in memory of Dr. Caspar Wistar (1761–1818). Questioned about the spelling later, Nuttall said it was for "euphony", but his biographer speculated that it may have something to do with Nuttall's friend Charles Jones Wister, Sr., of Grumblethorpe, the grandson of the merchant John Wister. (Some Philadelphia sources state that the plant is named after Wister.) As the spelling is apparently deliberate, there is no justification for changing the genus name under the International Code of Botanical Nomenclature. However, some spell the plant's common name "wistaria".
Genetic analysis shows Callerya and Wisteria to be each others' closest relatives and quite distinct from other members of the tribe Millettieae. Both have eight chromosomes.
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