Senna | |
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Senna alexandrina | |
Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Eudicots |
Clade: | Rosids |
Order: | Fabales |
Family: | Fabaceae |
Subfamily: | Caesalpinioideae |
Tribe: | Cassieae |
Genus: | Senna Mill. |
Type species | |
Senna alexandrina | |
Species | |
Over 300; see § Species | |
Synonyms [1] | |
List
|
Senna, the sennas, is a large genus of flowering plants in the legume family (Fabaceae, subfamily Caesalpinioideae, [2] tribe Cassieae ser. Aphyllae [3] ). This diverse genus is native throughout the tropics, with a small number of species in temperate regions. The number of species is estimated to be from about 260 [4] to 350. [5] The type species for the genus is Senna alexandrina . About 50 species of Senna are known in cultivation. [6]
Plants in the genus Senna are shrubs, sometimes small trees or perennial herbs. 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. The flowers are arranged in racemes in leaf axils with bracts at the base. The flower has five egg-shaped green or yellowish sepals and five usually yellow, usually glabrous petals. There are usually ten stamens that are free from each other, the filaments of different lengths, and some are staminodes. The fruit is a leathery pod containing several seeds. [7] [8] [9] [10]
Chamaecrista , Cassia , and Senna form a monophyletic group which some authors have called Cassia sensu lato . [11] In 1982, the group was named Cassiinae and classified as a subtribe of the tribe Cassieae. [12] The tribe Cassieae contains 21 genera and is now known to be polyphyletic, [11] but the classification is still accepted because a revision of Fabaceae has yet to be published. [11]
The genus Senna has had a complex taxonomic history. [13] What is now known as Senna was included by Linnaeus in his concept of Cassia in Species Plantarum in 1753. [14] Philip Miller segregated Senna from Cassia in 1754 in the fourth edition of The Gardeners Dictionary . [15] Until 1982, many authors, following Linnaeus, did not recognize Senna and Chamaecrista, but included them in a broadly circumscribed Cassia sensu lato . Phylogenetic analyses of DNA have shown that Chamaecrista, Cassia, and Senna are all monophyletic, but the relationships between these three genera have not been resolved. [4] They are therefore shown in phylogenetic trees as a tritomy.
A fossil seed pod of a Senna sp. from the middle Eocene epoch has been described from the Rancho clay pit in Henry County, Tennessee, United States. [16]
The genus name derives from the Arabic sanā, describing plants whose leaves and pods have cathartic and laxative properties. [17]
As of July 2024 [update] , Plants of the World Online accepted the following species: [18]
The caterpillars of many species feed on Senna plants. The black witch ( Ascalapha odorata ), two-barred flasher ( Astraptes fulgerator ), common emigrant ( Catopsilia pomona ), and mottled emigrant ( C. pyranthe ) have all been recorded on candle bush ( S. alata ), for example.
Some species have extrafloral nectaries on the leaves or flower stalks that are visited by ants. [4]
Senna species are pollinated by a variety of bees, especially large female bees in genera such as Xylocopa . [4] They rely on "buzz pollination" and some within that on "ricochet pollination", which is a secondary pollen presentation where the pollen is not deposited on the pollinator's body by direct contact with the anthers. [19] The flowers have two sets of stamen: feeding stamens, which are longer, and pollinating stamens, which are smaller in size. [20] Due to buzz pollination, the pollens from the pollinating stamens get thrown from the anthers and ricochets against the petals multiple times before it settles on the dorsal side of the pollinating bee. The roughness on the petal walls causes the pollen to slow down its speed. The ricocheting effect alone cannot ensure effective pollen dissemination. It is aided by static charges wherein the flying bees become positively charged owing to the friction in the air and the pollen becomes negatively charged because of which they naturally get attracted to the bee's body. The pollinator bee ends up carrying the pollen and also gets to feed on the pollen which is on the feeding stamens. [19]
Some Senna species are used as ornamental plants in landscaping. The genus is adapted to many climate types.
Cassia gum, an extract of the seeds of Chinese senna ( S. obtusifolia ), is used as a thickening agent. The leaves and flowers of Siamese cassia ( S. siamea ) are used in some Southeast Asian cuisines, such as Thai, Shan/Burmese and Lao cuisines. They are known as khi-lek in Thai, and are used in curries. [21]
Senna is considered[ who? ] to be a bowel stimulant on the myenteric plexus of the colon to induce peristaltic contractions and decrease water absorption from inside the colon, effects that would provide relief from constipation. [22] The laxative syrup of figs gets most of its effect from the presence of senna. [23]
Plants in the Senna genus have been studied for their beneficial effects arising from the abundance of phytochemicals, bioactive components and antioxidant and antimicrobial properties. [3]
Senna or its extracted sennosides, alone or in combination with sorbitol or lactulose, have been evaluated in systematic reviews and Cochrane reviews for treatment of constipation in children and the elderly. Some studies showed limited evidence for efficacy, [24] [25] [26] whereas others indicated the study designs were too weak to be certain of senna having utility as a laxative. [22] [27] [28]
Cassia is a genus of flowering plants in the legume family, Fabaceae, and the subfamily Caesalpinioideae. Species are known commonly as cassias. The genus includes 37 species and has a pantropical distribution. Species of the genera Senna and Chamaecrista were previously included in Cassia. Cassia now generally includes the largest species of the legume subtribe Cassiinae, usually mid-sized to tall trees.
Senna spectabilis is a plant species of the legume family (Fabaceae) in the subfamily Caesalpinioideae native to South and Central America. They are often grown as an ornamental in front yards, parks, gardens, buildings etc. due to their bright yellow flowers that bloom during the summer months. They are also known as golden wonder tree, American cassia, popcorn tree, Cassia excelsa, golden shower tree or Archibald's cassia.
Senna obtusifolia, known by common names including Chinese senna, American sicklepod and sicklepod, is a plant in the genus Senna, sometimes separated in the monotypic genus Diallobus. It grows wild in North, Central, and South America, Asia, Africa, and Oceania, and is considered a particularly problematic weed in many places. It has a long-standing history of confusion with Senna tora and that taxon in many sources actually refers to the present species.
Senna alexandrina is an ornamental plant in the genus Senna. It is used in herbalism. It grows natively in upper Egypt, especially in the Nubian region, and near Khartoum (Sudan), where it is cultivated commercially. It is also grown elsewhere, notably in India and Somalia.
Chamaecrista is a genus of flowering plants in the pea family, Fabaceae, subfamily Caesalpinioideae. Members of the genus are commonly known as sensitive pea. Several species are capable of rapid plant movement. Unlike the related genera Cassia and Senna, members of Chamaecrista form root nodules.
Zygia is a genus of flowering plants in the family Fabaceae. It includes 60 species of tres and shrubs native to the tropical Americas, from Southern Mexico and Cuba to northern Argentina. Typical habitats are tropical forest and coastal zones, generally below 900 meters elevation with a few species extending up to 2800 meters. It belongs to the mimosoid clade of the subfamily Caesalpinioideae.
Senna wislizeni, commonly called Wislizenus' senna or shrubby senna. Formerly in the "wastebin taxon" Cassia sensu lato, it is now placed in the genus Senna or sometimes separated in Palmerocassia together with Senna unijuga.
Cassia javanica, also known as Java cassia, pink shower, apple blossom tree and rainbow shower tree, is a species of tree in the family Fabaceae. Its origin is in Southeast Asia, but it has been extensively grown in tropical areas worldwide as a garden tree owing to its beautiful crimson and pink flower bunches.
Senna acclinis, commonly known as rainforest cassia or brush senna, is a species of flowering plant in the family Fabaceae and is endemic to near-coastal areas of eastern Australia. It is a shrub with pinnate leaves and bright golden yellow flowers in groups of two to five and long, narrow seed pods. It is similar to other species of Senna that are environmental weeds.
Pseudalbizzia is a genus of flowering plants in the pea family (Fabaceae). It includes 17 species which are native to the tropical Americas, from Mexico to northern Argentina.
Senna pendula, also known as Easter Cassia, Christmas Senna, winter Senna, climbing Cassia, golden shower, pendant Senna and valamuerto, is a plant of the Fabaceae family with a shrub habit that is native to South America. It used in various parts of the world as an ornamental plant and is an environmental weed in Australia. The flowers are yellow and the name pendula means 'pendulous' or 'drooping'.
Senna multijuga, commonly known as November shower or false sicklepod, is a species of flowering plant in the family Fabaceae. It is native to wet tropical areas of Latin America, and widely introduced to other tropical locales such as Africa, India, Indonesia, China, Australia, and Hawaii. A fast-growing tree typically 10 m (33 ft) tall, it is planted in restoration projects, as an ornamental, and as a street tree, being especially useful under power lines.
Senna aciphylla, commonly known as sprawling senna or Australian senna, is a species of flowering plant in the family Fabaceae and is endemic to eastern Australia. It is a sprawling shrub with pinnate leaves with eight to twelve pairs of linear to narrowly elliptic leaflets, and yellow flowers in pairs or groups of three.
Senna coronilloides, commonly known as brigalow senna, is a species of flowering plant in the family Fabaceae and is endemic to eastern Australia. It is an erect, sprawling shrub with pinnate leaves with nine to twelve pairs of elliptic leaflets, and groups of three to five yellow flowers in upper leaf axils.
Senna glutinosa is a species of flowering plant in the family Fabaceae and is endemic to central and northern arid areas of Australia. It is a shrub or small tree with pinnate leaves with up to seven pairs of leaflets, their shape depending on subspecies, and yellow flowers arranged in groups with ten fertile stamens in each flower.
Senna hirsuta, commonly known as woolly senna, is a species of flowering plant in the family Fabaceae and is native to Central and South America, but is naturalised in many other countries. It is an erect or spreading shrub or herbaceous perennial with pinnate leaves, with two to six pairs of egg-shaped leaflets, and yellow flowers arranged in groups of two to six, with six fertile stamens and four staminodes in each flower.
Senna leptoclada is a species of flowering plant in the family Fabaceae and is endemic to Arnhem Land in northern Australia. It is a glaucous, erect to drooping shrub with pinnate leaves usually with two pairs of broadly elliptic leaflets, and yellow flowers arranged in groups of two or three, with ten fertile stamens in each flower.
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