Colubrina (PROSEA)

Plant Resources of South-East Asia
Introduction

Colubrina Rich. ex Brongn.

Protologue: Mém. fam. Rhamn.: 61 (1826).

Family: Rhamnaceae

Chromosome number: x= 12; 2n= unknown for Asiatic species

Origin and geographic distribution

Colubrina comprises about 24 species, has a pantropical distribution, and is mainly centred in Central America. Three species are found throughout the Malesian region.

Uses

The wood of Colubrina is used for general construction and local house building.

Production and international trade

The wood of Colubrina is probably rarely used and only on a local scale.

Properties

Colubrina yields a heavy hardwood with a density of 1005-1065 kg/m³at 15% moisture content. Heartwood blood-red-brown, sharply differentiated from the narrow yellow sapwood; grain straight, but irregular in samples from small trees; texture fine and even. Growth rings visible, boundaries indicated by marginal parenchyma; vessels moderately small to medium-sized, solitary and in radial multiples of 2-8, the solitary ones typically larger than those in groups, open or filled with yellow-pink solid deposits; parenchyma moderately abundant, paratracheal scanty, vasicentric, and apotracheal in marginal or seemingly marginal bands, some diffuse; rays moderately fine to medium-sized, just visible to the naked eye on transverse and tangential surface; ripple marks absent.

The wood is very hard.

See also the table on microscopic wood anatomy.

Botany

Deciduous or evergreen shrubs or small to medium-sized trees up to 30 m tall; bole branchless for up to 20 m, up to 50 cm in diameter, sometimes with small buttresses or stilt roots; bark surface smooth to slightly dimpled, brittle, reddish-brown to dark brown, inner bark light red, pale yellow near the cambium. Leaves alternate, simple, entire to finely serrate, 3-veined at base; stipules minute, caducous. Inflorescence an axillary cyme or small thyrse, sessile or shortly peduncled. Flowers small, bisexual, 5(-6)-merous; hypanthium hemispherical to saucer-shaped; sepals keeled inside, caducous; petals clawed, hooded, greenish-yellow to yellow or rarely whitish; disk massive, fleshy; ovary semi-inferior, (2-)3(-4)-locular with 1 ovule in each cell, style usually 3-lobed or 3-fid. Fruit a globose capsule, orange-red to black, dehiscing explosively into 3 ventrally dehiscent stones. Seed reddish-brown to black, glossy.

Colubrina is probably the most primitive genus within the Rhamnaceae . The related Emmenosperma papuanum (Merr. & L.M. Perry) M.C. Johnston (synonym: Colubrina papuana Merr. & L.M. Perry) is a lesser-known timber from New Guinea used for general construction.

Ecology

C. beccariana is a typical representative of primary lowland rain forest, up to 200 m altitude.

Genetic resources and breeding

Being restricted to primary forest, the risk of genetic erosion depends on the extent of destruction of the habitat. Despite the comparatively large distribution area the occurrence of C. beccariana is scattered and local.

Prospects

Very little is known about the wood quality of Colubrina . It is unlikely that its use will increase in the near future.

Literature

163, 267, 505, 940, 1048, 1221, 1222.