Astronia (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Astronia Blume

Protologue: Bijdr. fl. Ned. Ind. 17: 1080 (1816).

Family: Melastomataceae

Chromosome number: x= unknown; 2n= unknown

Origin and geographic distribution

Astronia comprises about 60 species occurring in India, Burma (Myanmar), Indo-China, Taiwan, Thailand, and throughout the Malesian region towards the Pacific, east to Tahiti. About 20 species are found within the Malesian region: 2 in Peninsular Malaysia, 1 in Sumatra, 2 in Java, 2 in Borneo, 4 in Sulawesi, 4 in the Moluccas and 8 in New Guinea. 33 Species have been described from the Philippines, but the actual number is probably much lower.

Uses

The wood of Astronia is used for poles and planks in local house building and for tool handles. Occasionally, it is used for general construction purposes in the highlands of Papua New Guinea.

The leaves and bark of A. papetaria have been applied in sauces as "obat papeda" to add a sour flavour.

Production and international trade

Utilization of the wood of Astronia is very limited and on a local scale only.

Properties

Astronia yields a medium-weight hardwood with a density of 490-700 kg/m³at 15% moisture content. Wood pale brown. Growth rings indistinct; vessels moderately small to medium-sized, solitary and in radial multiples of 2-3; parenchyma paratracheal scanty and apotracheal diffuse; rays very fine; ripple marks absent.

The wood is non-durable and of moderate strength.

See also the table on microscopic wood anatomy.

Botany

Shrubs or small to medium-sized trees up to 20(-30) m tall; bole up to 80 cm in diameter, without buttresses, but often spurred; bark surface smooth to finely cracked or flaky and papery, peeling in long strips, greenish-brown to dark brown, inner bark straw to cream. Branches compressed to quadrangular, covered with reddish-brown scales but becoming glabrous. Leaves opposite or ternate, simple, entire, 3- or 5-veined from the base or slightly above the base, exstipulate, with small brown scales on lower surface. Flowers in a terminal or rarely axillary thyrse, sometimes unisexual by abortion, 5-merous; calyx cup-shaped, yellow-green, undulate to dentate, densely lepidote; petals free, white or purple; stamens 10, equal, anthers opening by slits, axe-shaped; ovary inferior and united with the calyx tube, 2-5-locular with many ovules in each cell, style short. Fruit a leathery, pale brown, subglobose, irregularly dehiscing, many-seeded capsule. Seed linear or oblanceolate.

In Java A. spectabilis flowers and fruits throughout the year.

Astronia belongs to the tribe Astronieae and is very similar to Astronidium with which it may eventually have to be united.

Ecology

Astronia species usually occur in primary lowland and lower montane forest, up to 1500 m altitude, sometimes in secondary forest or forest edges. A. spectabilis occurs in montane forest at 1300-2500 m altitude. A. atroviridis is found in mid-montane to upper montane forest up to 2800 m altitude.

Genetic resources and breeding

Species with a narrow geographical distribution (e.g. A. papetaria ) are vulnerable to genetic erosion.

Prospects

The importance of Astronia wood is extremely limited, partly because the wood properties have been little studied. This is unlikely to change in the near future, especially as the trees are small.

Literature

70, 79, 163, 300, 436, 497, 750, 785, 861, 1151, 1221, 1232.