Agrostistachys (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Agrostistachys Dalzell

Protologue: Hooker's Journ. Bot. Kew Gard. Misc. 2: 41 (1850).

Family: Euphorbiaceae

Chromosome number: x= unknown; 2n= unknown

Vernacular names

• Malaysia: jejulong, julong-julong (Peninsular), kayu garang (Sabah).

Origin and geographic distribution

Agrostistachys comprises about 8 species and occurs in Sri Lanka, India, Burma (Myanmar) and Indo-China towards Thailand and the Malesian region. The 4 species found in the latter area are distributed as follows: 3 in Peninsular Malaysia, 1 in Sumatra, 3 in Borneo, 2 in the Philippines, and 1 in Papua New Guinea.

Uses

The wood of Agrostistachys has been used for walking sticks, fence poles and carrying baskets. It is suitable for the production of pulp and yields a fairly good fuelwood. The logs are also suitable for mushroom cultivation.

The large leaves are used for roofing, thatching and wrapping. The fibrous bark can be used to make rope. The resin on the terminal bud is used to secure knife blades in their handles. The gum of A. borneensis used to be used to varnish sheaths and handles of krises.

Production and international trade

The wood of Agrostistachys is used on a local scale only.

Properties

Agrostistachys yields a medium-weight to heavy hardwood with a density of 685-940 kg/m³at 15% moisture content. Heartwood brown with a rose-pink tinge ( A. borneensis ) or pale yellow ( A. gaudichaudii ), not clearly differentiated from the sapwood; grain straight; texture fine and even. Growth rings mostly indistinct, sometimes delimited by a band of marginal parenchyma; vessels very small, mostly in radial multiples of 2-4, sometimes more; parenchyma sparse, apotracheal occasionally in marginal or seemingly marginal bands, visible to the naked eye, and diffuse, tending to diffuse-in-aggregates, visible only with a hand lens; rays very fine to moderately fine, visible only with a hand lens; ripple marks absent.

There is no information on the durability of this wood, but specimens in the wood collection of the Forest Research Institute Malaysia have not been attacked by fungi or borers.

See also the table on microscopic wood anatomy.

Botany

Dioecious, virtually glabrous, small trees up to 15 m tall; bole up to 25 cm in diameter, without buttresses; bark surface smooth; crown narrow and conical to domed and open. Terminal bud with a clear, inflammable, resinous coat. Leaves arranged spirally, in a tight terminal cluster, simple, oblanceolate to cuneate-obovate, up to 60 cm long, entire to dentate, without glands; stipules free, persistent or caducous. Flowers small, on axillary, single or grouped, short to elongate, bracteate spikes. Male flowers in clusters within each bract; calyx splitting into 2-5-segments; petals 5-8; disk composed of 5 glands; stamens (8-)10(-13), anther cells pendulous. Female flowers solitary; sepals 5; petals 5; ovary superior, 3-locular with a single ovule per cell, style entire or bifid. Fruit a crustaceous capsule seated on the blackened disk and the persistent, recurved sepals. Seed smooth.

Agrostistachys develops according to Corner's architectural tree model, characterized by the vegetative growth of a single meristem producing an unbranched axis on which the inflorescences are borne laterally.

Ecology

A. borneensis occurs locally gregarious in evergreen, lowland and lower montane, sometimes mossy forest, on hillsides and ridge tops, up to 1050 m altitude. It is found in kerangas, dipterocarp-fagaceous forest, low dipterocarp forest and swamp forest. A. gaudichaudii is found in lowland, evergreen forest, mainly on alluvial plains, up to 200 m altitude. Soil types include sandstone, yellow sandy clay, clay loam, and rarely white sand and limestone. Both species are understorey trees.

Silviculture Agrostistachys can be propagated from seed, which has a high germination percentage. Natural regeneration is generally good.

Genetic resources and breeding

As the two timber-yielding species are fairly common and their utilization is very restricted, the risk of genetic erosion is probably small.

Prospects

The utilization of Agrostistachys timber is unlikely to increase, since the bole is usually small. The wood may gain some importance for the production of pulp and chipboards, and as a fuelwood.

Literature

26, 28, 32, 33, 34, 81, 162, 163, 209, 267, 402, 543, 974, 834, 835, 1195, 1221, 1242.