Commercial Timbers

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H. G. Richter and M. J. Dallwitz

Alexa grandiflora Ducke, Alexa spp. (Melancieira)

Nomenclature etc. FABACEAE-FABOIDEAE. Including: Alexa imperatricis (Schomb.) Baker, A. leiopetala Sandwith, A. wachenheimii R. Ben., A. bauhiniaeflora Ducke. Trade and local names: melancieira (BR); haiariballi (GY); nekoe-oedoe (SR). Not protected under CITES regulations.

Tree. Geographic distribution: tropical South America.

General. Growth ring boundaries distinct (by marginal parenchyma bands). Heartwood basically brown and yellow white or grey, without streaks. Sapwood colour similar to heartwood colour. Odour indistinct or absent. Density 0.55–0.65 g/cm³.

Vessels. Vessels present. Wood diffuse-porous. Vessels arranged in no specific pattern, in multiples, commonly short (2–3 vessels) radial rows or radial rows of 4 or more. Average tangential vessel diameter 130–220(–270) µm. Average number of vessels/mm² 1–3. Average vessel element length 310–430–570 µm. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 5–7 µm, vestured. Vessel-ray pits with distinct borders, similar to intervessel pits. Helical thickenings absent. Tyloses in vessels absent. Other deposits in heartwood vessels present (light amber).

Tracheids and fibres. Vascular or vasicentric tracheids sporadic to absent. Fibres of medium wall thickness. Average fibre length 1000–1650–2150 µm. Fibre pits mainly restricted to radial walls, simple to minutely bordered. Helical thickenings absent. Fibres non-septate.

Axial parenchyma. Axial parenchyma present, banded. Axial parenchyma bands marginal (or seemingly marginal), fine, up to three cells wide. Axial parenchyma paratracheal. Paratracheal axial parenchyma aliform and confluent. Aliform parenchyma lozenge. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 3–5.

Rays. Rays 6–10 per tangential mm, multiseriate (also if only few), (1–)2(–3) cells wide. Rays with multiseriate portions as wide as uniseriate portions absent. Aggregate rays absent. Rays of one size. 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. Sheath cells absent. Tile cells absent. Perforated ray cells absent. Disjunctive ray parenchyma end walls indistinct or absent.

Storied structures. Storied structure absent.

Secretory structures. Oil and mucilage cells absent. Intercellular canals absent. Laticifers or tanniniferous tubes absent.

Cambial variants. Included phloem absent. Other cambial variants absent.

Mineral inclusions. Crystals present, prismatic, located in axial parenchyma cells. Crystal-containing axial parenchyma cells chambered. Number of crystals per cell or chamber one. Crystal containing cells of normal size. Cystoliths absent. Silica not observed.

Illustrations. • Transverse section. Alexa imperatricis. • Tangential section. Alexa imperatricis. • Radial section. Alexa imperatricis.


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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. http://delta-intkey.com’.

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