Commercial Timbers


H. G. Richter and M. J. Dallwitz

Cratoxylum arborescens Bl. (Geronggang)

Nomenclature etc. GUTTIFERAE. Trade and local names: geronggang (MY, ID); serugan (MY-sab). Not protected under CITES regulations.

Tree. Geographic distribution: Thailand, Laos, Vietnam, Cambodia, or Indomalesia.

General. Growth ring boundaries indistinct or absent. Heartwood basically light brown red, without streaks. Sapwood colour distinct from heartwood colour. Odour indistinct or absent. Density 0.42–0.55 g/cm³.

Vessels. Vessels present. Wood diffuse-porous. Vessels arranged in diagonal and/or radial pattern, in multiples, commonly short (2–3 vessels) radial rows or radial rows of 4 or more. Two distinct vessel diameter classes absent. Average tangential vessel diameter 150–250 µm. Average number of vessels/mm² 5–8. Some of the larger vessels typically appended with many small vessels either in radial rows or as irregular clusters. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 5–7 µm. Vessel-ray pits with distinct borders, similar to intervessel pits, of uniform size or type, of the same type in adjacent elements, located throughout the ray. Tyloses in vessels present, thinwalled. Other deposits in heartwood vessels present (reddish brown).

Tracheids and fibres. Vascular or vasicentric tracheids sporadic to absent. Fibres of medium wall thickness. Fibre pits mainly restricted to radial walls, simple to minutely bordered. Helical thickenings absent. Fibres non-septate.

Axial parenchyma. Axial parenchyma not banded. Axial parenchyma paratracheal. Paratracheal axial parenchyma scanty, or vasicentric. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 8–15.

Rays. Rays 8–11 per tangential mm, multiseriate (also if only few), 1–2(–3) cells wide. Rays with multiseriate portions as wide as uniseriate portions absent. Rays composed of two or more cell types (heterocellular). Heterocellular rays with square and upright cells restricted to marginal rows, mostly 1 marginal row of upright or square cells.

Storied structures. Storied structure absent.

Mineral inclusions. Crystals not observed. Silica present, as grains, in rays cells. Silica particles mostly small, more or less circular and with a smooth surface.

Illustrations. • Transverse section. Cratoxylum arborescens. • Tangential section. Cratoxylon arborescens. • Radial section. Cratoxylon arborescens. • Vessel groups. Cratoxylon arborescens. Note: Radial groups of very small vessels attached to large ones are a characteristic feature of this timber as seen in transverse (right) and radial (left margin) view.

The interactive key allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting specified attributes, summaries of attributes within groups of taxa, and geographical distribution.

Cite this publication as: ‘Richter, H.G., and Dallwitz, M.J. 2000 onwards. Commercial timbers: descriptions, illustrations, identification, and information retrieval. In English, French, German, Portuguese, and Spanish. Version: 25th June 2009.’.