''Alstonia'' is a widespread

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

evergreen In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, which ...

trees and

shrub A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees ...

s, of the family

Apocynaceae Apocynaceae (from ''Apocynum'', Greek for "dog-away") 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 ...

. It was named by Robert Brown in 1811, after Charles Alston (1685–1760), professor of

botany Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Ancient Greek w ...

Edinburgh Edinburgh ( ; gd, Dùn Èideann ) is the capital city of Scotland and one of its 32 Council areas of Scotland, council areas. Historically part of the county of Midlothian (interchangeably Edinburghshire before 1921), it is located in Lothian ...

from 1716 to 1760. The type species ''Alstonia scholaris'' (L.) R.Br. was originally named ''Echites scholaris'' by Linnaeus in 1767.

Description

''Alstonia'' consists of about 40–60

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

(according to different authors) native to tropical and subtropical

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

Central America Central America ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia to the south, the Caribbean Sea to the east, and the Pacific Ocean to the west. ...

Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical United Nations geoscheme for Asia#South-eastern Asia, south-eastern region of Asia, consistin ...

Polynesia Polynesia () "many" and νῆσος () "island"), to, Polinisia; mi, Porinihia; haw, Polenekia; fj, Polinisia; sm, Polenisia; rar, Porinetia; ty, Pōrīnetia; tvl, Polenisia; tkl, Polenihia (, ) is a subregion of Oceania, made up of ...

and

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

, with most species in the

Malesian region Malesia is a biogeographical region straddling the Equator and the boundaries of the Indomalayan and Australasian realms, and also a phytogeographical floristic region in the Paleotropical Kingdom. It has been given different definitions. The ...

. These trees can grow very large, such as ''Alstonia pneumatophora'', recorded with a height of 60 m and a diameter of more than 2 m. ''Alstonia longifolia'' is the only species growing in Central America (mainly shrubs, but also trees 20 m high). The leathery, sessile, simple

leaves A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...

are elliptical, ovate, linear or lanceolate and wedge-shaped at the base. The leaf blade is dorsiventral, medium-sized to large and disposed oppositely or in a whorl and with entire margin. The leaf venation is pinnate, with numerous veins ending in a marginal vein.

Phyllotaxy In botany, phyllotaxis () or phyllotaxy is the arrangement of leaves on a plant stem. Phyllotactic spirals form a distinctive class of patterns in nature. Leaf arrangement The basic arrangements of leaves on a stem are opposite and alternat ...

is whorled i.e. two or more leaves arises at a node and form a whorl . The

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...

is terminal or axillary, consisting of thyrsiform

cymes An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed on ...

or compound

umbel In botany, an umbel is an inflorescence that consists of a number of short flower stalks (called pedicels) that spread from a common point, somewhat like umbrella ribs. The word was coined in botanical usage in the 1590s, from Latin ''umbella'' "p ...

s. The small, more or less fragrant

flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...

s are white, yellow, pink or green and funnel-shaped, growing on a pedicel and subtended by

bract In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves. They may be smaller, larger, or of ...

s. They consist of 5

petal Petals are modified Leaf, leaves that surround the reproductive parts of flowers. They are often advertising coloration, brightly colored or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''c ...

s and 5

sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 The term ''sepalum'' was coined b ...

s, arranged in four whorls. The fertile flowers are hermaphrodite. The gamosepalous green sepals consist of ovate lobes, and are distributed in one whorl. The annular disk is hypogynous. The five gamesepalous petals have oblong or ovate lobes and are disposed in one whorl. The corolla lobes overlapping to the left (such as ''A. rostrata'') or to the right (such as ''A. macrophylla'') in the bud. The

ovary The ovary is an organ in the female reproductive system that produces an ovum. When released, this travels down the fallopian tube into the uterus, where it may become fertilized by a sperm. There is an ovary () found on each side of the body. ...

has 2 separate follicles with glabrous or ciliate, oblong

seed A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiospe ...

s that develop into deep blue podlike, schizocarp

fruit In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particu ...

, between 7–40 cm long. The plants contain a milky

latex Latex is an emulsion (stable dispersion) of polymer microparticles in water. Latexes are found in nature, but synthetic latexes are common as well. In nature, latex is found as a milky fluid found in 10% of all flowering plants (angiosperms ...

, rich in poisonous

alkaloid Alkaloids are a class of basic, naturally occurring organic compounds that contain at least one nitrogen atom. This group also includes some related compounds with neutral and even weakly acidic properties. Some synthetic compounds of similar ...

s. The ''Alstonia macrophylla'' is commonly known in

Sri Lanka Sri Lanka (, ; si, ශ්‍රී ලංකා, Śrī Laṅkā, translit-std=ISO (); ta, இலங்கை, Ilaṅkai, translit-std=ISO ()), formerly known as Ceylon and officially the Democratic Socialist Republic of Sri Lanka, is an ...

as 'Havari nuga' or the 'wig banyan' because of its distinct flower that looks like a woman's long wig. ''Alstonia'' trees are used in

traditional medicine Traditional medicine (also known as indigenous medicine or folk medicine) comprises medical aspects of traditional knowledge that developed over generations within the folk beliefs of various societies, including indigenous peoples, before the ...

. The bark of the '' Alstonia constricta'' and the ''

Alstonia scholaris ''Alstonia scholaris'', commonly called blackboard tree, Scholar Tree, Milkwood or devil's tree in English, is an evergreen tropical tree in the Dogbane Family (Apocynaceae). It is native to southern China, tropical Asia (mainly the Indian subcon ...

'' is a source of a remedy against

malaria Malaria is a mosquito-borne infectious disease that affects humans and other animals. Malaria causes symptoms that typically include fever, tiredness, vomiting, and headaches. In severe cases, it can cause jaundice, seizures, coma, or death. S ...

, toothache, rheumatism and snake bites. The

is used in treating coughs, throat sores and fever. Many ''Alstonia'' species are harvested for

timber Lumber is wood that has been processed into dimensional lumber, including beams and planks or boards, a stage in the process of wood production. Lumber is mainly used for construction framing, as well as finishing (floors, wall panels, wi ...

, called ''pule'' or ''pulai'' in Indonesia and Malaysia. Trees from the section ''Alstonia'' produce lightweight timber, while those from the sections ''Monuraspermum'' and ''Dissuraspermum'' produce heavy timber. ''Alstonia'' trees are widespread and mostly not endangered. However a few species are very rare, such as ''A. annamensis'', ''A. beatricis'', ''A. breviloba'', ''A. stenophylla'' and ''A. guangxiensis''.

Species

''Alstonia'' has five distinct sections, each a

monophyletic In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...

group; ''Alstonia'', ''Blaberopus'', ''Tonduzia'', ''Monuraspermum'', ''Dissuraspermum''. ;Accepted species # '' Alstonia actinophylla'' (A.Cunn.) K.Schum. – milkwood - New Guinea, N Australia # ''

Alstonia angustifolia ''Alstonia angustifolia'' is a species of plant in the family Apocynaceae. It is found in Indonesia, Malaysia, the Philippines, and Vietnam Vietnam or Viet Nam ( vi, Việt Nam, ), officially the Socialist Republic of Vietnam,., group="n ...

'' A.DC. - Borneo, W Malaysia, Sumatra # ''

Alstonia angustiloba ''Alstonia angustiloba'' is a tree in the dogbane family Apocynaceae. Description ''Alstonia angustiloba'' grows as a large tree up to tall, with a trunk diameter of up to . The bark is greyish or brownish. Its fragrant flowers feature a white, ...

'' Miq. - Borneo, W Malaysia, Sumatra, Thailand, Java # '' Alstonia annamensis'' (Monach.) K.Sidiyasa - Cambodia, Vietnam # '' Alstonia balansae'' Guillaumin - New Caledonia # '' Alstonia beatricis'' K.Sidiyasa - Waigeo I in E Indonesia # '' Alstonia boonei'' De Wild. - W + C + E Africa # '' Alstonia boulindaensis'' Boiteau - New Caledonia # ''

Alstonia breviloba ''Alstonia breviloba'' is a species of plant in the family Apocynaceae. It is endemic to Papua New Guinea Papua New Guinea (abbreviated PNG; , ; tpi, Papua Niugini; ho, Papua Niu Gini), officially the Independent State of Papua New Gu ...

'' K.Sidiyasa - Papua New Guinea # ''

Alstonia congensis ''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. The root and stem bark co ...

'' Engl. - W + C Africa # '' Alstonia constricta'' F.Muell. – bitterbark, quinine tree, Australian fever bark - E Australia # '' Alstonia coriacea'' Pancher & S.Moore - New Caledonia # '' Alstonia costata'' R.Br. - S Pacific # '' Alstonia curtisii'' King & Gamble - Thailand # '' Alstonia deplanchei'' Van Heurck & Müll.Arg. - New Caledonia # '' Alstonia guangxiensis'' D.Fang & X.X.Chen - Guangxi in China # '' Alstonia iwahigensis'' Elmer - Borneo, Palawan # '' Alstonia lanceolata'' Van Heurck & Müll.Arg. - New Caledonia # '' Alstonia lanceolifera'' S.Moore - New Caledonia # '' Alstonia legouixiae'' Van Heurck & Müll.Arg. - New Caledonia # ''

Alstonia lenormandii ''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. The type species ''Alsto ...

'' Van Heurck & Müll.Arg. - New Caledonia # ''

Alstonia longifolia ''Alstonia longifolia'' is a plant species in the genus ''Alstonia'', family Apocynaceae. It is native to southern Mexico and Guatemala Guatemala ( ; ), officially the Republic of Guatemala ( es, República de Guatemala, links=no), is a c ...

'' (A.DC.) Pichon - Mexico, Central America # ''

Alstonia macrophylla ''Alstonia macrophylla'', the hard alstonia, hard milkwood or big-leaved macrophyllum, is a species of plant in the family Apocynaceae. Distribution It is native to Indonesia (Kalimantan and Sulawesi), Malaysia, the Philippines ( Tagalog: ''bati ...

'' Wall. ex G.Don – batino, devil tree - S China, Sri Lanka, SE Asia, New Guinea # ''

Alstonia mairei ''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. The type species ''Alsto ...

'' H. Léveillé - S China, N Vietnam # ''

Alstonia muelleriana ''Alstonia muelleriana'' is a tree in the dogbane family Apocynaceae which is native to southern Papua New Guinea and northeastern Queensland. Description ''Alstonia muelleriana'' is an evergreen tree growing to between in height. The leaves ...

'' Domin – jackapple, leatherjacket, milky yellowwood - New Guinea, Queensland # '' Alstonia neriifolia'' D.Don - Nepal, Sikkim, Bhutan # '' Alstonia odontophora'' Boiteau - New Caledonia # '' Alstonia parkinsonii'' (M.Gangop. & Chakrab.) Lakra & Chakrab. - Andaman Is. # ''

Alstonia parvifolia ''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. The type species ''Alsto ...

'' Merr. - Philippines # '' Alstonia penangiana'' K.Sidiyasa - Penang Hill in Malaysia # '' Alstonia pneumatophora'' Backer ex L.G.Den Berger - W Malaysia, Borneo, Sulawesi, Sumatra # '' Alstonia quaternata'' Van Heurck & Müll.Arg. - New Caledonia # '' Alstonia rostrata'' C.E.C.Fischer - Yunnan, Indochina, W Malaysia, Sumatra # ''

Alstonia rubiginosa ''Alstonia rubiginosa'' is a species of plant in the family Apocynaceae. It is endemic to Papua New Guinea Papua New Guinea (abbreviated PNG; , ; tpi, Papua Niugini; ho, Papua Niu Gini), officially the Independent State of Papua New G ...

'' K.Sidiyasa - Papua New Guinea # '' Alstonia rupestris'' Kerr - Thailand # ''

'' (L.) R.Br. – pali-mari, dita bark, bitter bark, milkwood, milky bean, milky pine, white cheesewood, scholar tree, blackboard tree - E + S + SE Asia, Papuasia, N Australia # ''

Alstonia sebusii ''Alstonia sebusii'', synonym ''Alstonia henryi'', is a species of flowering plant in the family Apocynaceae, native to the region of Assam, south-central China, the east Himalayas and Myanmar. It was first described in 1871 as ''Blaberopus se ...

'' (Van Heurck & Müll.Arg.) Monach. - Yunnan, Bhutan, Assam, N Myanmar # ''

Alstonia spatulata ''Alstonia spatulata'', also called hard milkwood or Siamese balsa, is a species of tree in the family Apocynaceae. It is found in Cambodia, Indonesia, Laos, Malaysia, Papua New Guinea, the Philippines, Singapore, Thailand, and Vietnam V ...

'' Blume – hard milkwood, Siamese balsa - SE Asia, New Guinea # '' Alstonia spectabilis'' R.Br. – poele bark, jackapple, leatherjacket, milky yellowwood - SE Asia, Papuasia, N Australia # ''

Alstonia sphaerocapitata ''Alstonia'' is a widespread genus of evergreen trees and shrubs, of the family Apocynaceae. It was named by Robert Brown (botanist, born 1773), Robert Brown in 1811, after Charles Alston (botanist), Charles Alston (1685–1760), professor of bot ...

'' Boiteau - New Caledonia # '' Alstonia venenata'' R.Br. - S India # '' Alstonia vieillardii'' Van Heurck & Müll.Arg. - New Caledonia # '' Alstonia vietnamensis'' D.J.Middleton - Vietnam # '' Alstonia yunnanensis'' Diels - Yunnan, Guizhou, Guangxi

Gallery

Alstonia scholaris (Saptaparni) in Hyderabad, AP W IMG 1469.jpg, ''

'' Alstonia spectabilis Blanco2.379.png, '' Alstonia spectabilis'' Alstonia macrophylla (Batino) in Hyderabad W IMG 7138.jpg, ''

Notes

References

* * Kade Sidiyasa, A., 3, 1992. A monograph of Alstonia (Apocynaceae). * {{Taxonbar, from=Q2475725 Apocynaceae genera