![]() Until 1982, many authors, following Linnaeus, did not recognize Senna and Chamaecrista, but included them in a broadly circumscribed Cassia sensu lato. Philip Miller segregated Senna from Cassia in 1754 in the fourth edition of The Gardeners Dictionary. What is now known as Senna was included by Linnaeus in his concept of Cassia in Species Plantarum in 1753. The genus Senna has had a complex taxonomic history. The tribe Cassieae contains 21 genera and is now known to be polyphyletic, but the classification is still accepted because a revision of Fabaceae has yet to be published. In 1982, the group was named Cassiinae and classified as a subtribe of the tribe Cassieae. Systematics Ĭhamaecrista, Cassia, and Senna form a monophyletic group which some authors have called Cassia sensu lato. The fruit is a leathery pod containing several seeds. There are usually ten stamens that are free from each other, the filaments of different lengths, and some are staminodes. The flower has five egg-shaped green or yellowish sepals and five usually yellow, usually glabrous petals. The flowers are arranged in racemes in leaf axils with bracts at the base. The leaves are arranged alternately, paripinnate with up to 25 pairs of leaflets, each leaf with a stipule at the base, but that often falls off as the leaves mature. ![]() ![]() Plants in the genus Senna are shrubs, sometimes small trees or perennial herbs. About 50 species of Senna are known in cultivation. The type species for the genus is Senna alexandrina. The number of species is estimated to be from about 260 to 350. This diverse genus is native throughout the tropics, with a small number of species in temperate regions. Senna, the sennas, is a large genus of flowering plants in the legume family ( Fabaceae, subfamily Caesalpinioideae, tribe Cassieae). ![]()
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