Glenniea (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Glenniea Hook. f.

Protologue: Benth. & Hook. f., Gen. pl. 1: 404 (1862).

Family: Sapindaceae

Chromosome number: x= unknown; 2n= unknown

Glenniea comprises 8 species, 3 of which are found in tropical Africa, 1 in Madagascar, 1 in Sri Lanka and 3 within the South-East Asian region in Vietnam, south-eastern Thailand, Peninsular Malaysia, Sumatra, Borneo, the Philippines and New Guinea.

The wood of Glenniea is suitable for carving and fine furniture.

The bark is easily inflammable and used for kindling fires. G. philippinensis is a rare edible fruit tree.

Glenniea wood is probably used rarely and on a local scale only.

Glenniea yields a medium-weight hardwood with a density of 630-705 kg/m³at 15% moisture content. Heartwood pale yellow-brown or yellowish, not differentiated from the sapwood; grain straight; texture moderately fine and even; prominent vessel lines present as in Pometia . Growth rings distinct to the naked eye, boundary indicated by marginal parenchyma bands; vessels medium-sized, solitary and in radial multiples of 2-3, open or containing pale solid deposits; parenchyma moderately abundant, apotracheal in marginal or seemingly marginal bands, and paratracheal vasicentric, the latter form just visible to the naked eye; rays very fine to moderately fine, visible to the naked eye; ripple marks absent.

The wood is moderately hard and susceptible to sap-stain.

See also the table on microscopic wood anatomy.

Monoecious or dioecious, small to medium-sized trees up to 36 m tall; bole straight, up to 70(-100) cm in diameter, fluted or sometimes with plank buttresses; bark surface smooth to slightly fissured, inner bark hard gritty, yellowish-brown. Leaves arranged spirally or partly decussate, unifoliolate or paripinnate, 1-6-jugate, exstipulate; leaflets opposite or alternate. Flowers in a terminal or axillary thyrse or panicle, unisexual, 4-5-merous; sepals connate at base, valvate to narrowly imbricate in bud; petals absent; stamens 6 or 7; disk annular; ovary superior, 2-locular with 1 ovule in each cell; style conical, stigma 2-lobed or grooved. Fruit a large berry. Seed without arillode. Seedling with hypogeal germination; cotyledons not emergent; hypocotyl not elongated; epicotyl strongly elongated and scaly; first 1-9 leaves simple and alternate-spiral, subsequent ones imparipinnate, followed by paripinnate ones.

Trees generally flower twice a year. Pollination is by insects, probably bees. The fruits are eaten and dispersed by birds and mammals.

G. penangensis and G. thorelii are found in primary lowland rain forest; the first up to 1000 m altitude, the second up to 200 m altitude on alluvial plains, river banks, slopes and ridges. G. philippinensis occurs in thickets and riverine forest at low altitude.

Silviculture Glenniea may be raised from seed. G. penangensis seeds show about 50% germination in 20-35(-124) days.

G. philippinensis is rare, whereas G. penangensis is endemic to Peninsular Malaysia. Both species are at risk of genetic erosion by habitat destruction.

Since the timber is seldom used and wood properties are poorly known the utilization of Glenniea is unlikely to increase in the near future.

151, 235, 267, 341, 686, 687, 829, 831, 934, 1048, 1164, 1221.