Family : Apocynaceae
Text © Pietro Puccio
English translation by Mario Beltramini
The species is native to Borneo, Java, Peninsular Malaysia, Singapore, Sumatra and Thailand where it grows in the mixed forests of dipterocarps and swampy forests, where often is one of the dominant species, from the sea level up to about 400 m of altitude.
The genus is honoured to the Scottish physician and botanist Charles Alston (1685-1760); the specific name is the combination of the Latin adjective “angustus, a, um” = thin and “lobus, a, um” = lobe, with reference to the lobes of the flower.
Common names: pulai tree (English); pantung, pelai, pulai, pulai bukit, pulai lilin (Bornean); pulai hitam (Indonesian); pulai, pulai bukit (Malaysian); mergalang (Sarawakian); gabus, goti, pelaik, pelawai, pulai, pule, tuturan (Sumatran); tin pet lek (Thai).
The Alstonia angustiloba Miq. (1857) is an up to more than 40 m tall semideciduous tree with erect trunk up to more than 1 m of diameter, provided at the base of tabular roots (flat roots similar to buttresses that help to supporting the great trees), up to 6 m tall, and greyish white to brown bark, smooth in the young specimens, then rough and vertically fissured; all parts of the plant contain a white latex exuding abundantly from the wounds.
The leaves, on a 1-3 cm long petiole grooved on top, are simple, arranged in verticils of 4-7, obovate to elliptic-oblong with attenuated base and slightly obtuse or pointed apex, curved entire margins and prominent central nervation, 4-15 cm long and 2-6 cm broad, coriaceous, of glossy green colour above, greenish grey below.
The inflorescences are compound umbel terminal carrying numerous imbutiform hermaphroditic flowers, with cylindrical tube slightly elated above, 0,6 cm long and 5 oblong-linear lobes, about 0,4 cm long, of cream white colour; the flowers emit an intense scent.
The fruits are dehiscent cylindrical follicles, curved, thin, brown and tomentose, up to 25 cm long and 0,3 cm of diametre, containing numerous seeds, almost rectangular, flat, about 0,5 cm long, provided of a tuft of silky hairs, 1 cm long, on the two extremities for favouring the dispersion through the wind. It reproduces by seed, in draining loam rich of humus maintained humid at the temperature of 24-26 °C, that germinates with a high percentage in 2-8 weeks, and by cutting.
Species of great ornamental and landscape value, of easy cultivation and fast growth, amply utilized, due to its luxuriant foliage and the intense scent of its flowers, in parks and gardens, as isolated specimen or in group, and as road tree in the tropical and subtropical climate countries, with high annual rainfall well distributed, in particular in south-eastern Asia; is also employed in the reforestation. Requires high constant temperatures, an exposition in full sun and grows in a vast variety of soils, average acidic to average alkaline, provided maintained almost constantly humid.
It is cultivated also for the wood, light and tender, easy to work, with which are produced tools and several common use objects (boxes, matches, pencils, sandals, etc.) and artistic, and for the fabrication of the paper.The various parts of the plant are used since remote times in the popular medicine, laboratory studies have evidenced the presence of numerous alkaloids with promising properties for the employment in various fields of the medicine, in particular in the context of cancer and malaria treatment.
Synonyms: Alstonia calophylla Miq. (1857); Alstonia angustiloba var. glabra Koord. & Valeton (1894); Paladelpha angustiloba (Miq.) Pichon (1947).