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Nomenclature etc. APOCYNACEAE. Alstonia scholaris R.Br., Alstonia spathulata Bl., A. angustiloba Miq. Trade and local names: sua, mo cua (VN); tin pet (MM); dita (PH); chatian (IN); white cheesewood, deviltree, ditabark, milkwood "pine" (AU, GB); tang jiao shu (CN);. Not protected under CITES regulations.
Description based on 6 specimens. Tree. Geographic distribution: India, Pakistan, Sri Lanka, Myanmar (Burma), Thailand, Laos, Vietnam, Cambodia, Indomalesia.
General. 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 in short (2–3 vessels) radial rows. Vessel outline angular. Average tangential vessel diameter 80–150–190 µm. Average number of vessels/mm² 3–8. Average vessel element length 600–900(–1250) µm. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 4–7 µm, pits vestured. Vessel-ray pits with distinct borders, similar to intervessel pits. Helical thickenings absent. Tyloses absent. Other deposits present (rare).
Tracheids and fibres. Fibres very thin-walled. Average fibre length 1100–1300–1750 µm. Fibre pits mainly restricted to radial walls, simple to minutely bordered. Fibres non-septate.
Axial parenchyma. Axial parenchyma banded. Bands marginal (or seemingly marginal) and not marginal (or seemingly marginal). Axial parenchyma bands forming a reticulate pattern with rays. Bands fine to coarse. Apotracheal axial parenchyma diffuse to diffuse-in-aggregates. Paratracheal axial parenchyma scanty. Axial parenchyma as strands. Average number of cells per strand: 5–13.
Rays. Rays 5–9(–11) per tangential mm, multiseriate, (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.
Storied structures. Storied structure 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.
Physical and chemical tests. Heartwood not fluorescent. Water extract fluorescent (yellowish); colour of water extract colourless to brown. Ethanol extract not fluorescent. Colour of ethanol extract colourless to brown. Froth test weakly positive. Splinter burns to partial ash. Ash bright white.
Illustrations. • Macroscopic images. transverse (ca. 10x). longitudinal (natural size). • Transverse section. Alstonia scholaris. vessels in long radial multiples. vessels in short radial multiples. • Tangential section. Alstonia pneumatophora. prismatic crystals (Cr) and latex ltube (Lt). Cr »». Lt »». • Radial section. Alstonia scholaris. • Crystals; lacticifers. typical features in Alstonia (section Alstonia): Prismatic crystals in chambered parenchyma cells (left) and latex tubes 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: 9th April 2019. delta-intkey.com’.
