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{{Short description|Species of tree}}
{{Speciesbox
|image = Alstonia.scholaris.jpg
|image_caption = Blackboard tree (''Alstonia scholaris'')
|status = LC
|status_system = IUCN3.1
|status_ref = <ref name=IUCN>{{cite iucn | author1 = Lakhey, P. | author2 = Pathak, J. | name-list-style = amp | title = ''Alstonia scholaris'' | page = e.T32295A2812825 | year = 2021| access-date = 11 November 2022}}</ref>
|genus = Alstonia
|species = scholaris
|authority = ([[Carl Linnaeus|L.]]) [[Robert Brown (botanist, born 1773)|R.Br.]]
|range_map = Alstoniascholaris1.png
|range_map_caption = Occurrence data from [[GBIF]]<ref name=gbif>GBIF.org (07 June 2018) GBIF Occurrence Download https://doi.org/10.15468/dl.eokqvq Alstonia scholaris (L.) R.Br.</ref>
|synonyms_ref = <ref name=GRIN/>
|synonyms =
{{Species list| Echites scholaris | L.}}
}}

'''''Alstonia scholaris''''', commonly called '''blackboard tree''', '''scholar tree''', '''milkwood''' or '''devil's tree''' in English,<ref name=GRIN/> 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.

==Description==
''Alstonia scholaris'' is a [[glabrousness (botany)|glabrous]] tree and grows up to {{convert|40|m|abbr=on}} tall. Its mature bark is grayish and its young branches are copiously marked with [[lenticel]]s. 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).<ref>{{cite book | date= 1925 | last= Lane-Poole | first= C.E. | title= Forest Resources of the Territories of Papua and New Guinea | location= Melbourne | publisher= Government Printer | page= 134}}</ref>

The upper side of the leaves are glossy, while the underside is greyish.<ref name=stuart>{{cite web |url=http://www.stuartxchange.org/Dita.html |title=Dita / Alstonia scholaris / WHITE CHEESE WOOD / Tang jiao shu /: Philippine Medicinal Herbs / Philippine Alternative Medicine |website=www.stuartxchange.org |access-date=29 June 2007}}</ref> Leaves occur in [[Whorl (botany)|whorls]] of three to ten; [[Petiole (botany)|petiole]]s are {{convert|1–3|cm|abbr=on}}; the leathery leaves are narrowly [[obovate]] to very narrowly [[spathulate]], base cuneate, apex usually rounded and up to {{cvt|23|cm|abbr=on}} long by up to {{cvt|8|cm|abbr=on}} in width.<ref>{{cite book | date= 1952 | last= Corner | first= Prof. E.J.H. | title= Wayside Trees of Malaya - Volume 1 | location= Singapore | publisher= Govt Printing Office | page= 141}}</ref> lateral veins occur in 25 to 50 pairs, at 80–90° to midvein. [[Cyme (botany)|Cymes]] are dense and pubescent; [[Peduncle (botany)|peduncle]] is {{convert|4–7|cm|abbr=on}} long. [[Pedicel (botany)|Pedicel]]s are usually as long as or shorter than [[sepal|calyx]]. The [[Corolla (flower)|corolla]] is white and tube-like, {{convert|6–10|mm|abbr=on}}; lobes are broadly [[Glossary of botanical terms#ovate|ovate]] or broadly obovate, {{convert|2-4.5|mm|abbr=on}}, overlapping to the left. The ovaries are distinct and pubescent. The [[follicle (fruit)|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 {{convert|1.5–2|cm|abbr=on}}.<ref name=efloras>{{cite web |url=http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=200018323 |title= |website=www.efloras.org |access-date=29 June 2007}}{{SemiBareRefNeedsTitle|date=May 2022}}</ref> The bark is almost odorless and very bitter, with abundant bitter and milky [[sap]].

==Distribution==
''Alstonia scholaris'' is native to the following regions:<ref name=GRIN>{{GRIN | access-date=2012-03-30}}</ref>

* China: [[Guangxi]], [[Yunnan]]
* [[Indian subcontinent]]: Bangladesh, India, Nepal, Pakistan, Sri Lanka
* [[Southeast Asia]]: Cambodia, Laos, Indonesia, Malaysia, Myanmar, Papua New Guinea, Philippines, Thailand, Vietnam<ref>Simon Gardner, Pindar Sidisunthorn and Lai Ee May, 2011. ''Heritage Trees of Penang''. Penang: Areca Books. {{ISBN|978-967-57190-6-6}}</ref>
* Australia: [[Queensland]]

''Alstonia scholaris'' is the state tree of [[West Bengal#Flora and fauna|West Bengal]], India, where it is called Chhatim tree.

==Toxicity==
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]].<ref name=Baliga2004>{{cite journal |last1=Baliga |first1=Manjeshwar Shrinath |last2=Jagetia |first2=Ganesh Chandra |last3=Ulloor |first3=Jagadish N. |last4=Baliga |first4=Manjeshwar Poonam |last5=Ponemone |first5=Venkatesh |last6=Reddy |first6=Rosi |last7=Rao |first7=Mallikarjun K. V. N. |last8=Baliga |first8=Shivanada Bantwal |last9=Devi |first9=Sulochana |last10=Raju |first10=Sudheer Kumar |last11=Veeresh |first11=Veerapura |last12=Reddy |first12=Tiyyagura Koti |last13=Bairy |first13=Laxminarayana K. |date=2004 |title=The evaluation of the acute toxicity and long term safety of hydroalcoholic extract of Sapthaparna (''Alstonia scholaris'') in mice and rats |url=http://eprints.manipal.edu/314 |journal=Toxicology Letters |volume=151 |issue=2 |pages=317–326 |doi=10.1016/j.toxlet.2004.01.015|pmid=15183456 }}</ref>

==Uses==
[[Image:Saptaparni (Alstonia scholaris) leaves & flowers in Kolkata W IMG 0534.jpg|thumb|left| Leaves and flowers in [[Kolkata]], [[West Bengal]], [[India]]]]
The wood of ''Alstonia scholaris'' has been recommended for the manufacture of [[Pencil#Wood holders added|pencil]]s, as it is suitable in nature and the tree grows rapidly and is easy to cultivate.<ref>Tonanont, N. Wood used in pencil making. Vanasarn 1974 Vol. 32 No. 3 pp. 225–227</ref> In Sri Lanka its light wood was used for [[coffin]]s. The wood close to the root is very light and of white colour, and in [[Borneo]] was used for net floats, household [[food utensil|utensil]]s, [[Trencher (tableware)|trencher]]s, corks, etc.<ref>{{cite book|chapter-url=http://www.botanical.com/botanical/mgmh/a/alsto028.html |last=Grieve |first=M. |chapter=''Alstonia'' |title=A Modern Botanical |date=1931 |location= |publisher= |access-date=29 June 2007}}</ref> 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'']."<ref>{{cite book | author=J. H. Maiden | year=1889 | title=The useful native plants of Australia : Including Tasmania |location=Sydney | publisher=Turner and Henderson | url=https://primo-slnsw.hosted.exlibrisgroup.com/primo-explore/fulldisplay?docid=SLNSW_ALMA21105097830002626&context=L&vid=SLNSW&search_scope=EEA&tab=default_tab&lang=en_US}}</ref> 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]]''.<ref name=Wright1993>{{cite journal |last1=Wright |first1=Colin W. |last2=Allen |first2=David |last3=Phillipson |first3=J. David |last4=Kirby |first4=Geoffrey C. |last5=Warhurst |first5=David C. |last6=Massiot |first6=Georges |last7=Le Men-Olivier |first7=Louisette |date=September 1993 |title=''Alstonia'' species: are they effective in malaria treatment? |journal=Journal of Ethnopharmacology |volume=40 |issue=1 |pages=41–45 |doi=10.1016/0378-8741(93)90087-L|pmid=8246529 }}</ref><ref name=Wright1992>{{cite journal |last1=Wright |first1=C. W. |last2=Allen |first2=D. |last3=Cai |first3=Ya |last4=Phillipson |first4=J. D. |last5=Said |first5=I. M. |last6=Kirby |first6=G. C. |last7=Warhurst |first7=D. C. |date=June 1992 |title=In vitro antiamoebic and antiplasmodial activities of alkaloids isolated from ''Alstonia angustifolia'' roots |journal=Phytotherapy Research |volume=6 |issue=3 |pages=121–124 |doi=10.1002/ptr.2650060303|s2cid=86802484 }}</ref> It had no effect against ''[[Giardia intestinalis]]'',<ref name=Wright1993/> and weak effect against ''[[Entamoeba histolytica]]'', which both cause diarrhoea.<ref name=Wright1992/>

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]].<ref name="The Hindu">{{cite news | author = Abhishek Gulshan | date = 22 October 2019 | title = Why the Saptaparni is called the devil's tree | url = https://www.thehindu.com/sci-tech/energy-and-environment/why-the-saptaparni-is-called-the-devils-tree/article29767114.ece | newspaper = [[The Hindu]] | access-date = 14 February 2023}}</ref>

At one time, [[decoction]]s of the leaves were used for [[beriberi]].<ref name=stuart/>

==Chemistry==
The bark contains the [[alkaloid]]s [[ditamine]], [[echitenine]],{{citation needed|date=November 2014}} [[echitamine]]<ref name=Baliga2004/> and [[strictamine]].<ref>{{cite journal | pmid = 500142 | year = 1979 | last1 = Bhattacharya | first1 = S. K. | title = Neuropharmacological studies on strictamine isolated from ''Alstonia scholaris'' | journal = Indian Journal of Experimental Biology | volume = 17 | issue = 6 | pages = 598–600 | last2 = Bose | first2 = R. | last3 = Dutta | first3 = S. C. | last4 = Ray | first4 = A. B. | last5 = Guha | first5 = S. R. }}</ref> 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]].<ref>{{cite journal |last1=Yamauchi |first1=Tatsuo |last2=Abe |first2=Fumiko |last3=Padolina |first3=William G. |last4=Dayrit |first4=Fabian M. |date=1990 |title=Alkaloids from leaves and bark of ''Alstonia scholaris'' in the Philippines |url=https://www.academia.edu/7426110 |journal=Phytochemistry |volume=29 |issue=10 |pages=3321–3325 |doi=10.1016/0031-9422(90)80208-X |bibcode=1990PChem..29.3321Y |access-date=1 July 2021}}</ref>

==Gallery==
<gallery>
File:Devil Tree Blossom.jpg|''Alstonia scholaris'' blossom – Mumbai, India
File:Alstonia scholaris4922818774 2c30e78d11 o.jpg|''Alstonia scholaris'' fruit, Australia
Image:Alstonia scholaris by kadavoor.JPG|Arrangement of leaves
Image:Alstonia scholaris.jpg|''Alstonia scholaris'' in the IIT Kanpur campus
Image:Bark of Alstonia scholaris.jpg|Close-up of bark in Hong Kong
</gallery>

==References==
{{Commons category|Alstonia scholaris}}
{{Reflist}}

{{West Bengal}}
{{Taxonbar|from=Q135307}}

[[Category:Alstonia|scholaris]]
[[Category:Flora of Guangxi]]
[[Category:Flora of Yunnan]]
[[Category:Flora of tropical Asia]]
[[Category:Trees of Australia]]
[[Category:Gentianales of Australia]]
[[Category:Flora of Queensland]]
[[Category:Least concern flora of Australia]]
[[Category:Least concern biota of Queensland]]
[[Category:Symbols of West Bengal]]

Alstonia scholaris - Revision history

Svetlanayrd: small changes

Ajay Kumar: Created a new article