Mitragyna hirsuta Havil. - RUBIACEAE

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Botanical descriptions Habitat and ecology Distribution

Botanical descriptions :

Diagnostic characters : Deciduous trees. Leaves simple, opposite ovate to obovate, hairy below, 5-6 nerves at base not reaching apex. Stipules interpetiolar, large, ovate and flattened. Flowers in a terminal head. Fruit capsular, seeds winged.
Habit : Deciduous tree up to 15 m. tall, 20 cm. in DBH.
Trunk & bark : Trunk pock marked, lenticelled, yellowish-green, outer bark yellowish-green when young then scaly and flaky, inner bark salmon, sapwood white.
Branches and branchlets or twigs : Branches with two serial buds, partly lenticellate; twigs terete, glabrous.
Exudates : Exudate absent.
Leaves : Leaves simple, opposite, crowded at the apex of branchlets, ovate to elliptic to obovate, 10-12 x 15-20 cm., blade subcoriaceous, pallidly hairy below, margin entire, apex acute to acuminate; base truncate.
Midrib grooved above, prominent below, the 6 veins from base do not reach to the apex. Secondary vein obtuse, 9-12 pairs and with domatia in axils. Interpetiolar stipule ovoid to elliptic or obovoid, flattened, slightly to strongly keeled, those subtending the flowering heads sometime leaf-like about 2 cm. long.
Inflorescences or flowers : Flowering head terminal on the side shoots of lateral branches, yellowish-white then turning black, up to 4 cm. in diameter. White style exserted.
Fruits : Fruit a sphaerical head of dehiscent fruitlets these free from one other surmounted with a persistent calyx. Capsules ellipsoid to ovoid, dehiscent.
Seeds : Seeds numerous, small and winged at both end.

Habitat and ecology :

In open dry Dipterocarp and Fagaceous forests, and degraded forests from 500 to 600 m. altitude.

Distribution :

Thailand, Vietnam and Laos.

Remark/notes/uses :
Boiled bark is used to relieve itching on the skin. The hard wood is very good for construction and fire wood.

Specimens studied :
BT 485, BT 502 and Lao 582 (Herbarium of Faculty of Sciences-NUoL, NHN-Leiden and CIRAD-Montpellier).

Literature :
Kessler P.J.A. (ed.) 2000. Secondary forest trees of Kalimantan, Indonesia. MOFEC Tropenbos Kalimantan Series 3. The Netherlands.
Puff C., K. Chayamarit and V. Chamchumroon. 2005. Rubiaceae of Thailand. A pictorial guide to indigenous and cultivated genera. The Forest Herbarium, National Park, Wildlife and Plant Conservation Department, Bangkok.

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