Alstonia rostrata C.E.C.Fisch. - APOCYNACEAE

Synonym : Winchia calophyllaA.DC.
Winchia glaucescens K.Schum.
Alstonia glaucescens (K. Schum) Monachino
Alstonia undulifolia Kochummen & Wong.

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Botanical descriptions Habitat and ecology Distribution

Botanical descriptions :

Diagnostic characters : Trees with white latex. Leaves in whorl; flowers white with recurved and overlapping petal lobes, puberulent at both side.
Habit : Tree up to 30 m. tall, branches ascending to main trunk. Bole generally fluted at base.
Trunk & bark : Trunk with low buttresses. Bark fissured, longitudinally lenticellate, pale yellow, inner bark brownish-yellow.
Branches and branchlets or twigs : Branches terete, irregular and glabrous, brownish when dry, strongly lenticellate.
Exudates : Latex white in trunk and leaves.
Leaves : Leaves simple, grouped in whorls of 5-14 cm. by 1.6-5.5 cm., oblong or elliptic, apex acuminate or strongly acuminate, base attenuate and decurrent, margin undulate, young leaves brownish, blade coriaceous and glabrous.
Midrib flat above, prominent below, secondary vein very closely parallel, 35-56 pairs. Petiole with very small intrapetiolar stipule at base and with scale-like collecters in the axils.
Inflorescences or flowers : Flowers white, grouped in umbel-like, corolla tubes lobes, overlapping, finely velvety both side, slightly sweet smell.
Fruits : The fruits are solitary follicles of 12-19.5 by 0.7-0.8 cm. with thick walled and glabrous.
Seeds : Seeds numerous, 1 x 0.25 cm. glabrous and ciliate at both ends.

Habitat and ecology :

In evergreen or open degraded forests from 500 to 1300 m. altitude.
Flowering period: February to April; fruiting time: April to May.

Distribution :

China, Malay Peninsula, Burma (Myanmar), Thailand, Vietnam, Sumatra and Laos (Khammouan).

Remark/notes/uses :
The wood is often used for coffins and as a plywood core. An infusion of the crushed leaves is used to clean infected wounds. The bitter bark and latex yield a tonic and anti-septic medicine.

Specimens studied :
BT 35 and P 67 (Herbarium of Faculty of Sciences-NUoL, NHN-Leiden and CIRAD-Montpellier).

Literature :
Flora of Thailand. 1970-2002. Vol. 2, part 1. Forest Herbarium, Royal Forest Department, Bangkok, Thailand.
Gardner S., Sidisunthorn P. & Anusarnsunthorn V. 2000. A field guide to Forest Trees of Northern Thailand. Kobfai Publishing Project. Bangkok. Thailand.
Lecomte H. (ed.). 1907-1912. Flore Générale de l'Indo-Chine. Vol. 3 (8-9), Muséum National d’Histoire Naturelle, Laboratoire de Phanérogamie, Paris, France.

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