| Senna occidentalis | |
|---|---|
_Senna_occidentalis_-_Habit_-_Les_Martels,_Giroussens_Tarn.jpg)
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| Habit | |
Scientific classification 
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| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Rosids |
| Order: | Fabales |
| Family: | Fabaceae |
| Subfamily: | Caesalpinioideae |
| Genus: | Senna |
| Species: | S. occidentalis
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| Binomial name | |
| Senna occidentalis | |
| Synonyms[2] | |
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List
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Senna occidentalis, commonly known as coffee senna, styptic weed,[3] or septicweed,[4] is a species of flowering plant in the family Fabaceae and is native to the southern United States of America, Mexico and South America. It is a shrub with pinnate leaves, with three to seven pairs of broadly elliptic to egg-shaped leaflets, and yellow flowers arranged in groups of two to four, with six fertile stamens in each flower. It is an aggressive, pantropical weed.
Senna occidentalis is a foetid shrub that typically grows to a height of 1–2 m (3 ft 3 in – 6 ft 7 in) and has softly-hairy branches and stems. Its leaves are pinnate, 150–170 mm (5.9–6.7 in) long on a petiole 20–40 mm (0.79–1.57 in) long, with three to seven pairs of broadly elliptic to egg-shaped leaflets 50–70 mm (2.0–2.8 in) long and 30–40 mm (1.2–1.6 in) wide, spaced 15–30 mm (0.59–1.18 in) apart. There is a sessile glands near the base of the petiole.[3][5]
The flowers are yellow and arranged on the ends of branchlets and in upper leaf axils in groups of two to four on a peduncle 2–5 mm (0.079–0.197 in) long, each flower on a pedicel 10–15 mm (0.39–0.59 in) long. The petals are up to 10 mm (0.39 in) long and there are six fertile stamens, the anthers varying in length from 4 to 6 mm (0.16 to 0.24 in) long, and four staminodes. Flowering occurs all year, and the fruit is a cylindrical pod 120–180 mm (4.7–7.1 in) long, about 3 mm (0.12 in) wide and slightly curved.[3][5]
This species was first formally described in 1753 by Carl Linnaeus who gave it the name Cassia occidentalis in Species Plantarum from specimens collected in Jamaica.[6][7] In 1829, Link transferred the species to the genus Senna as S. occidentalis in his Handbuch zur Erkennung der nutzbarsten und am häufigsten vorkommenden Gewachse.[8][9] The specific epithet (occidentalis) means "western".[10]
Coffee senna is native to the southern United States of America, Mexico and South America,[2] but is an aggressive, pantropical weed. In Australia it is widespread but scattered in the north of Western Australia,[11] the Northern Territory,[12] South Australia, Queensland and New South Wales.[3][5]
The plant is reported to be poisonous to cattle,[13] because it contains a known toxic derivative of anthraquinone called emodin.[14] and the seeds contain chrysarobin (1,8-dihydroxy-3-methyl-9-anthrone) and N-methylmorpholine.[15]
Despite the claims of being poisonous, the leaves of this plant, Dhiguthiyara in the Maldivian language,[16] have been used in the diet of the Maldives for centuries[17] in dishes such as mas huni and also as a medicinal plant.[18]
Almost all parts (leaf, root, seeds) of the plant are used as food and medicine by tribal populations in India. However, consumption of Bana Chakunda seeds has been identified as a possible cause of death of tribal children due to acute Encephalopathy (see Acute HME syndrome).[19][20] Once the plant was identified as the cause, the number of deaths plummeted.[21]
The same thing happened in Rio Grande do Sul, Brazil, where 16 outbreaks were recorded.[22] This was a record in comparison to the clinical study of 1979, at which eight calves died after contracting dyspnea, neutrophilia and tachycardia from consumption of the plant.[23]
