Commercial Timbers


H. G. Richter and M. J. Dallwitz

Alstonia spp. - section Alstonia (Pulai)

Nomenclature etc. APOCYNACEAE. Alstonia scholaris R.Br., Alstonia spathulata Bl., A. angustiloba Miq. Trade and local names: pulai (MY, ID); sua, mo cua (VN); tin pet (MM); dita (PH); chatian (IN); white cheesewood (AU, GB). Not protected under CITES regulations.

Description based on 6 specimens. Tree. Geographic distribution: India, Pakistan, Sri Lanka, Burma, Thailand, Laos, Vietnam, Cambodia, and Indomalesia.

General. Growth ring boundaries indistinct or absent. Heartwood basically yellow white or grey. Sapwood colour similar to heartwood colour. Density 0.33–0.51 g/cm³.

Vessels. Wood diffuse-porous. Vessels in multiples, commonly short (2–3 vessels) radial rows. Vessel outline angular. Average tangential vessel diameter 80–150–190 µm; diameter of vessel lumina: large. Average number of vessels/mm² 3–8; vessels per square millimetre very few to few. Average vessel element length 600–900(–1250) µm. Average vessel element length medium to long. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 4–7 µm, vestured. Vessel-ray pits with distinct borders, similar to intervessel pits. Tyloses in vessels absent. Other deposits in heartwood vessels present (rare).

Tracheids and fibres. Vascular or vasicentric tracheids sporadic to absent. Fibres very thin-walled. Average fibre length 1100–1300–1750 µm. Average fibre length medium to long. Fibre pits mainly restricted to radial walls, simple to minutely bordered. Fibres non-septate.

Axial parenchyma. Axial parenchyma present, banded. Axial parenchyma bands marginal (or seemingly marginal) and not marginal (or seemingly marginal), reticulate, fine, up to three cells wide to coarse, more than three cells wide. Axial parenchyma apotracheal to paratracheal. Apotracheal axial parenchyma diffuse-in-aggregates. Paratracheal axial parenchyma scanty. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 5–13.

Rays. Rays 5–9(–11) per tangential mm, multiseriate (also if only few), (1–)2–3 cells wide. Height of large rays up to 500 µm to commonly 500 to 1000 µm. 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 or mostly 2–4 marginal rows of upright or square cells. Sheath cells absent.

Secretory structures. Laticifers or tanniniferous tubes present. Latex tubes sporadically in rays.

Mineral inclusions. Crystals present, prismatic, located in ray cells or axial parenchyma cells. Crystal-containing ray cells upright and/or square. Crystal-containing axial parenchyma cells chambered. Number of crystals per cell or chamber one, or more than one. Crystals in one cell or chamber of the same size, or of two distinct sizes. Silica not observed.

Illustrations. • Macro images. Alstonia sp. Transverse. Longitudinal. • Transverse section. Alstonia scholaris. Vessels in long radial multiples. Vessels in short radial multiples. • Tangential section. Alstonia pneumatophora. Note prismatic crystals (Cr) and latex laticifer (Lc). Cr . Lc . • Radial section. Alstonia scholaris. • Miscellaneous. Typical features in Alstonia (section Alstonia): Prismatic crystals in chambered parenchyma cells (left) and laticifers in rays (right).

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.’.