Euonymus (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Euonymus L.

Protologue: Sp. pl. 1: 197 (1753); Gen. pl., ed. 5: 91 (1754).

Family: Celastraceae

Chromosome number: x= 16 (or 8?);E. japonicusThunb.: 2n= 32, many extra-Malesian species have 2n= 32 or 64

Vernacular names

• Spindle tree (En). Bonnet de prêtre (Fr)
• Indonesia: awa kudang-kudang (Sumatra), jerukan (Javanese), ki keuyeup (Sundanese)
• Malaysia: belimbing hutan, belungkas, kemuning ayer (Peninsular)
• Philippines: malasangki (Filipino), talangutingon (Cebu Bisaya)
• Thailand: khao kwang, kraduuk kai (peninsular).

Origin and geographic distribution

Euonymus comprises some 180 species, most of which occur in the Himalayas, China and Japan. Europe has 4 species, Africa 1, Madagascar 2, North and Central America 9, Australia 2, and Malesia 12. The only Malesian species yielding timber is E. javanicus Blume (synonyms: E. coriaceus Ridley, E. micropetalus Ridley, E. sumatranus Miq.), which occurs in the Andaman and Nicobar Islands, southern Burma (Myanmar), southern Vietnam, peninsular Thailand, and throughout the Malesian region, east to western New Guinea (Vogelkop).

Uses

The wood of E. javanicus has been used for house building, temporary constructions, bridges and small furniture. In India its wood and that of several other Euonymus species is suitable for carving and turnery and may be used as a substitute for boxwood ( Buxus spp.) for making small articles such as spindles, pegs, spoons and toothpicks.

Production and international trade

Supplies of wood of E. javanicus are very limited, and it is used on a local scale only, if at all.

Properties

E. javanicus yields a medium-weight hardwood with a density of 620-760 kg/m³at 15% moisture content. Heartwood white to pale yellowish-brown, not clearly differentiated from the sapwood; grain straight; texture very fine and even. Growth rings distinct, demarcated by denser fibres; vessels extremely small, solitary and in radial pairs, individually indistinct, even with a hand lens, open; parenchyma not visible with a hand lens; rays extremely fine; ripple marks absent.

The wood is fairly strong, but only moderately durable when in contact with the ground. It is reputed to be very resistant to weathering and insects.

See also the tables on microscopic wood anatomy and wood properties.

Botany

An evergreen, small to medium-sized tree up to 25 m tall; bole up to 50 cm in diameter, without buttresses; bark surface smooth, grey-brown, inner bark pinkish. Leaves opposite, often decussate, simple, entire or crenate; stipules lanceolate, caducous. Flowers bisexual, in an axillary fascicle or a simple cyme, 5-merous; calyx deeply lobed; petals imbricate, fimbriate, pale green or yellowish; disk 5-angular; stamens inserted on or near the margin of the disk; ovary superior, partly sunken in the disk, 5-locular with 2 ovules in each cell, style short. Fruit a usually clavate or broadly obovoid capsule, red, splitting into valves. Seed black, partly covered by an orange aril. Seedling with epigeal germination; cotyledons emergent; hypocotyl elongated.

In the Philippines E. javanicus has been observed flowering in February and March.

Ecology

E. javanicus occurs scattered in primary and secondary, lowland to montane forest, up to 2400 m altitude. It has been found in well-drained locations on comparatively basic soils including limestone.

Silviculture E. javanicus is not resistant to fire.

Genetic resources and breeding

The wide geographical distribution of E. javanicus and its insignificant use for timber suggest that there is no risk of genetic erosion.

Prospects

Due to its frequently small size, the use of E. javanicus for timber will remain very restricted. It has been suggested for soil protection at altitudes of 1000-1500 m.

Literature

61, 70, 116, 163, 198, 235, 238, 259, 341, 371, 436, 772, 861, 974, 1038, 1048, 1221.

K.M. Kochummen