Alstonia in Malesia

Alstonia is a widespread genus of evergreen trees and shrubs, of the dogbane plant family Apocynaceae.  It consists of about 40-60 species, native to tropical and subtropical Africa, Central America, southeast Asia, Polynesia and Australia.

Nomeclature¹

Alstonia was named by Robert Brown in 1811, after Charles Alston (1685–1760), a professor of botany at Edinburgh from 1716-1760.

Description¹

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

The inflorescence is terminal or axillary, consisting of thyrsiform cymes or compound umbels. The small, more or less fragrant flowers are white, yellow, pink or green and funnel-shaped, growing on a pedicel and subtended by bracts. They consist of 5 petals and 5 sepals, arranged in four whorls. The fertile flowers are hermaphrodite.

Sections^1&2

Alstonia has 5 distinct sections, each a monophyletic group; Alstonia ( including Winchia ), Blaberopus, Tonduzia. Monuraspermum, and Dissuraspermum.

Species of the section Memuraspermum have no latex in the trunk bark, in contrast to the species of section Alstonia, where latex may be observed in all parts of the plant.

The leaves of Alstonia are opposite or whorled.  Opposite leaves are found in most species of Dissuraspermum.  Worled leaves are found in the other sections.

   

Distribution³

Alstonia species native to Malay Archipelago :

A. angustifolia A.DC. - Borneo, Malaya, Sumatra

A. angustiloba Miq. - Borneo, Malaya, Sumatra, Thailand, Java

A. curtisii King & Gamble - Thailand

A. glancescens Guillaumin - New Caledonia

A. macrophylla Wall. ex G.Don –  S China, Sri Lanka, SE Asia, New Guinea

A. neriifolia D.Don - Nepal, Sikkim, Bhutan

A. parvifolia Merr. - Philippines

A. penangiana K.Sidiyasa - Penang Hill

A. pneumatophore Backer ex L.G.Den Berger - Malaya, Borneo, Sulawesi, Sumatra

A. rupestris Kerr - Thailand

A. scbolaris (L.) R.Br.  - E+S+SE Asia, Papuasia, N Australia

A. spatulata Blume - SE Asia, New Guinea

A. spectabilis R.Br.  - SE Asia, Papuasia, N Australia

Conservation⁴

Alstonia trees are widespread and mostly not endangered.

Endangered : A. annamensis …

Vulnerable : A. penangiana, A. beatricis, A, breviloba, Al rubiginosa …

Least Concern : A. angustifolia, A. macrophylla, A. pneumatophore, A. rupestris, A. scholaris, A. spatulata, A. spectabilis …

Source:

1. Wikipedia

2. Kade Sidiyasa, 1998, Taxonomy, Phylogeny, and Wood Anatomy of Alstonia

3. Joseph Monachino, 1949, A Revision of the Genus Alstonia, PACIFIC SCIENCE, Vol. III. April 1949

4. IUCN Red List

Alstonia angustiloba - Pulai

Alstonia angustiloba Miq. ( synonym : Alstonia angustiloba var.glabra Koord. & Valeton., Alstonia calophylla Miq., Alstonia iwahigensis Elmer, Paladelpha angustiloba ( Miq.) Pichon ) is a species of evergreen tree in the Apocynacee family originated from S.E.Asia.  It is commonly called common pulai, pulai bukit, pulai lilin, pulantan bubur, pantung,  tombailik, gite, hanju latung, etc.

The name ‘Alstonia’ was named by Robert Brown in 1811, after Charles Alston (1685-1760), a Professor of botany at Edinburgh from 1716-1760.  ‘angustiloba’ means small lobes.

A fat-growing, medium-seized tree capable to reach up to 45m in height.  At full size, develop fluted buttresses.  Often split into two or more upright stems.  Outer bark brown , rough.  White latex in trunk and leaves when cut.  

Leaves are simple whorled.  Leaf oblong, tip obtuse to acute,  Petiole 10-20mm long.

Flower hermaphroditic.  Inflorescence terminal, flower white, tubular.  Usually 2 umbels above each other.

Fruits long thin follicles, seeds with tufts of hair at both ends, dispersed by wind.

The trees are often deciduous at irregular intervals.  

They do not flower at every leaf-change, but only after marked periods of dry weather.  Pollination is by insects.

Propagation is by seeds. Germination of fresh seed is nearly 100%.  Cleft grafting and inverted T-grafting also have been found to be successful.

Uses

Food : The latex provides a good quality chewing gum. 

Timber : The wood yield a good quality pulp for paper production.   It is used for pencil, matches, crates, patternmaking, corestock, plywood, carving and mouldings.  In Ceylon, coffins are made of this light wood. 

Landscape : It is also used in landscape as ornamental tree.