Pterospermum semisagittatum (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Pterospermum semisagittatum Buch.-Ham. ex Roxb.

Family: Sterculiaceae

• Cambodia: priël praëhs
• Laos: ham 'a:w, ham f'a:n
• Thailand: hamkhua (northern), kranuan (north-eastern), hamrok (peninsular)
• Vietnam: lòng mang mác, vỏ mương.

From India and Sri Lanka to Cambodia, Laos and Thailand.

In Vietnam, Cambodia and Laos the bark is used as a masticatory as a substitute for areca nuts (the endosperm of Areca catechu L.). The wood is used for axe handles and as fuelwood.

A small to medium-sized tree up to 25 m tall; bole up to 12 m; bark reddish. Leaves alternate, almost distichous, simple; stipules laciniate, about 2 cm long; petiole thick, about 3 mm long; blade lanceolate, 17-20 cm × 4-6 cm, base strongly sagittate, margin entire, apex long acuminate, lower surface woolly. Flowers few together in a leaf axil with laciniate bracts about 1.5 cm long; pedicel 0.5-1 cm long; involucral bracts 3, deeply 5-lobed, 2.0-4.5 cm long; calyx cylindrical, 4-8 cm long, with 5 narrow sepals; petals 5, oblanceolate, c. 5.5 cm × 2.0 cm, white; stamens in 5 bundles of 3, staminodes 5; ovary superior, 5-locular with many ovules in each cell, tomentose, style hairy at base. Fruit a tubular, fusiform to ovoid, woody capsule, up to 8 cm × 6 cm, with persistent calyx. Seed flattened, 4 cm long including the 3 cm long wing on one side. The wood is fairly hard, durable, 640-800 kg/m³at 15% moisture content, reddish-grey. P. semisagittatum is found in primary and secondary, evergreen forest at 100-900 m altitude. In Thailand it flowers in April-June and fruits in May-September.

15, 28, 51, 61, 66.

M.S.M. Sosef