Alstonia scholaris | |
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Blackboard tree (Alstonia scholaris) | |
Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Eudicots |
Clade: | Asterids |
Order: | Gentianales |
Family: | Apocynaceae |
Genus: | Alstonia |
Species: | A. scholaris |
Binomial name | |
Alstonia scholaris | |
Occurrence data from GBIF [2] | |
Synonyms [3] | |
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Alstonia scholaris, commonly called blackboard tree, scholar tree, milkwood or devil's tree in English, [3] is an evergreen tropical tree in the Dogbane Family (Apocynaceae). It is native to southern China, tropical Asia (mainly the Indian subcontinent and Southeast Asia) and Australasia, where it is a common ornamental plant. It is a toxic plant, but is used traditionally for myriad diseases and complaints.
Alstonia scholaris is a glabrous tree and grows up to 40 m (130 ft) tall. Its mature bark is grayish and its young branches are copiously marked with lenticels. A unique feature of this tree is that in some places, such as New Guinea, the trunk is three-sided (i.e. it is triangular in cross-section). [4]
The upper side of the leaves are glossy, while the underside is greyish. [5] Leaves occur in whorls of three to ten; petioles are 1–3 cm (0.39–1.18 in); the leathery leaves are narrowly obovate to very narrowly spathulate, base cuneate, apex usually rounded and up to 23 cm (9.1 in) long by up to 8 cm (3.1 in) in width. [6] lateral veins occur in 25 to 50 pairs, at 80–90° to midvein. Cymes are dense and pubescent; peduncle is 4–7 cm (1.6–2.8 in) long. Pedicels are usually as long as or shorter than calyx. The corolla is white and tube-like, 6–10 mm (0.24–0.39 in); lobes are broadly ovate or broadly obovate, 2–4.5 mm (0.079–0.177 in), overlapping to the left. The ovaries are distinct and pubescent. The follicles are distinct and linear.
Flowers bloom in the month October. The flowers are very fragrant similar to the flower of Cestrum nocturnum .
Seeds of A. scholaris are oblong, with ciliated margins, and ends with tufts of hairs 1.5–2 cm (0.59–0.79 in). [7] The bark is almost odorless and very bitter, with abundant bitter and milky sap.
Alstonia scholaris is native to the following regions: [3]
Alstonia scholaris is the state tree of West Bengal, India, where it is called Chhatim tree.
This is a toxic plant. At high doses, an extract of the plant exhibited marked damage to all the major organs of the body in both rats and mice. The toxicity appears to depend on the plant organ studied, as well as the season it is harvested, with the bark collected in the monsoon season being the least toxic, and bark in the summer the most. Intraperitoneal administration is much more toxic than oral. Rats were more susceptible to the poison than mice, and pure-bred mice strains were more susceptible than crossbred. The toxic effects may be due to the echitamine content of the bark, an alkaloid. [9]
The wood of Alstonia scholaris has been recommended for the manufacture of pencils, as it is suitable in nature and the tree grows rapidly and is easy to cultivate. [10] In Sri Lanka its light wood was used for coffins. The wood close to the root is very light and of white colour, and in Borneo was used for net floats, household utensils, trenchers, corks, etc. [11] In Theravada Buddhism, the first Buddha is said to have used Alstonia scholaris as the tree for achieving enlightenment.
The 1889 book The Useful Native Plants of Australia states that "the powerfully bitter bark of this tree is used by the natives of India in bowel complaints (Treasury of Botany). It has proved a valuable remedy in chronic diarrhoea and the advanced stages of dysentery. It has also been found effectual in restoring the tone of the stomach and of the system generally in debility after fevers and other exhausting diseases (Pharmacopoeia of India). It is described in the Pharmacopoeia of India as an astringent tonic, anthelmintic, and antiperiodic. It is held in the highest repute in the Phillippine Islands [sic]." [12] Despite its widespread traditional use as an 'antiperiodic' (a medicine which was supposed to cure the effects of malaria), it was found to have little to very weak activity against Plasmodium falciparum . [13] [14] It had no effect against Giardia intestinalis , [13] and weak effect against Entamoeba histolytica , which both cause diarrhoea. [14]
During convocation the leaves of Alstonia scholaris (saptaparni) are awarded to graduates and postgraduates of Visva-Bharati University by the chancellor, given to him in turn by the Prime Minister of India. In recent years, supposedly to prevent excessive damage to the environment, the vice-chancellor of the University accepts one saptaparni leaf from the chancellor on behalf of all the students. This tradition was initiated by the founder of the University, Rabindranath Tagore. [15]
At one time, decoctions of the leaves were used for beriberi. [5]
The bark contains the alkaloids ditamine, echitenine,[ citation needed ] echitamine [9] and strictamine. [16] Echitamine is the most important alkaloid found in the bark, as it has been detected in all samples studied and collected from several locations, and which is commercially sold as herbal medicine. [17]
Quercus montana, the chestnut oak, is a species of oak in the white oak group, Quercus sect. Quercus. It is native to the eastern United States, where it is one of the most important ridgetop trees from southern Maine southwest to central Mississippi, with an outlying northwestern population in southern Michigan. It is also sometimes called rock oak because of its presence in montane and other rocky habitats.
Apocynaceae is a family of flowering plants that includes trees, shrubs, herbs, stem succulents, and vines, commonly known as the dogbane family, because some taxa were used as dog poison. Members of the family are native to the European, Asian, African, Australian, and American tropics or subtropics, with some temperate members. The former family Asclepiadaceae is considered a subfamily of Apocynaceae and contains 348 genera. A list of Apocynaceae genera may be found here.
Salix alba, the white willow, is a species of willow native to Europe and western and central Asia. The name derives from the white tone to the undersides of the leaves.
Alstonia is a widespread genus of evergreen trees and shrubs, of the family Apocynaceae. It was named by Robert Brown in 1811, after Charles Alston (1685–1760), professor of botany at Edinburgh from 1716 to 1760.
Strychnos nux-vomica, the strychnine tree, also known as nux vomica, poison fruit, semen strychnos, and quaker buttons, is a deciduous tree native to India and to southeast Asia. It is a medium-sized tree in the family Loganiaceae that grows in open habitats. Its leaves are ovate and 5–9 centimetres (2–3.5 in) in size. It is known for being the natural source of the extremely poisonous compound strychnine.
Taxus cuspidata, the Japanese yew or spreading yew, is a member of the genus Taxus, native to Japan, Korea, northeast China and the extreme southeast of Russia.
Adenanthera pavonina is a perennial and non-climbing species of leguminous tree. Its uses include food and drink, traditional medicine, and timber.
Kleinhovia hospita is an evergreen, tropical tree native to Indonesia, Malaysia and other parts of tropical Asia and the Pacific. It is monotypic, being the only species in the genus Kleinhovia.
Alstonia macrophylla, the hard alstonia, hard milkwood or big-leaved macrophyllum, is a species of plant in the family Apocynaceae.
Laburnum anagyroides, the common laburnum, golden chain or golden rain, is a species of flowering plant in the subfamily Faboideae, and genus Laburnum. Laburnum alpinum is closely related. It is native to Central and Southern Europe.
Alstonia constricta, commonly known as quinine bush or bitterbark, is an endemic Australian endemic shrub or small tree of the family Apocynaceae.
Duboisia myoporoides, or corkwood, is a shrub or tree native to high-rainfall areas on the margins of rainforest in eastern Australia. It has a thick and corky bark. The leaves are obovate to elliptic in shape, 4–15 cm long and 1–4 cm wide. The small white flowers are produced in clusters. This is followed by globose purple-black berries.
Acalypha indica is an herbaceous annual that has catkin-like inflorescences with cup-shaped involucres surrounding the minute flowers. It is mainly known for its root being attractive to domestic cats, and for its various medicinal uses. It occurs throughout the Tropics.
Solanum erianthum is a species of nightshade that is native to southern North America and northern South America. It has been introduced to other parts of the world and has a nearly pantropical distribution. Common names include mullein nightshade, velvet nightshade, and salvadora. The potatoes are not the fruits of the trees, they are the leaves.
Litsea glaucescens, also called Mexican bay leaf, is an evergreen tree or shrub 3–6 metres (9.8–19.7 ft) high in the genus Litsea belonging to family Lauraceae. It is native from southern North America, mostly in Mexico. Distributed by Mexico and Central America.
Stereospermum kunthianum is an African deciduous shrub or small tree occurring in the Democratic Republic of Congo, Djibouti, Eritrea, Ethiopia, Kenya, Malawi, Senegal, Somalia, Sudan, Tanzania and Uganda. It is widespread across Africa to the Red Sea, and reaches as far south as Angola, Mozambique, Zambia and Zimbabwe. There are some 30 species with a Central African and Asian distribution.
Flacourtia montana is a plant in the family of Salicaceae. It is native to southern Asia. The species presents as a tree up to 20 m in height.
Alstonia congensis, is a tree within the Apocynaceae family and one of two African species within the Alstonia genus, the other being the Alstonia boonei De Wild. Both have similar morphological characteristics.
Annickia polycarpa is a small to medium-sized tree found in evergreen forests of West and Central Africa, it is within the Annonaceae family. It is also called the African Yellow wood.
Zanthoxylum avicennae is a woody plant in the family Rutaceae.