Tabebuia spp. (Ipé, lapacho, pau d'arco)
Nomenclature etc. BIGNONIACEAE. Tabebuia heptaphylla (Vell.) Toledo - Syn.: T. ipe (Mart.) Standl., Tecoma ipe Mart.; T. serratifolia (Vahl) Nichols.- Syn.: Tecoma serratifolia G. Don. Trade and local names: ipé, capitary, carobeira, pau d'arco (BR); arco, canuguate, guyacán (CO); arahonie, ebéne vert (FGU); taiy (PY); groenheart (SME); arcwood, bastard lignum vitae (USA). Status of protection under CITES regulations: not protected.
Description based on: 4 specimens. Tree. Geographic distribution: tropical South America, southern Brazil, and temperate South America.
General. Growth ring boundaries distinct. Heartwood basically brown, yellow, and green, with streaks. Sapwood colour distinct from heartwood colour. Odour indistinct or absent. Basic specific gravity 0.8–1.2 g/cm³. Wood with bitter taste, sawdust can cause skin irritation (Berni 1982).
Vessels. Vessels present. Wood diffuse-porous. Vessels arranged in no specific pattern, in multiples, commonly short (2–3 vessels) radial rows. Vessel outline rounded. Two distinct vessel diameter classes absent. Average tangential vessel diameter 60–95–175 µm. Average tangential diameter of vessel lumina medium. Average number of vessels/mm² 23–40. Vessels per square millimetre numerous. Average vessel element length 200–300 µm. Average vessel element length short. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 10–14 µm, large, not vestured. 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. Helical thickenings absent. Tyloses in vessels present, thinwalled. Other deposits in heartwood vessels present, organic subtance, yellow, known as "lapachol" or "ipeina".
Tracheids and fibres. Fibres very thick-walled. Average fibre length 700–900 µm. Average fibre length short. 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. Marginal parenchyma bands 1–2 cells wide, some discontinuous. Axial parenchyma paratracheal. Paratracheal axial parenchyma scanty, vasicentric, aliform, confluent, and unilateral paratracheal. Aliform parenchyma winged. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 2–4. Unlignified parenchyma absent.
Rays. Rays present, 5–11 per tangential mm, multiseriate, also if only few, 2–3(–4) cells wide, 2–3 cells wide. Rays with multiseriate portions as wide as uniseriate portions absent. Aggregate rays absent. Rays of one size. Height of large rays up to 500 µm. Rays composed of a single cell type. Homocellular ray cells procumbent. Sheath cells absent. Tile cells absent. Perforated ray cells absent. Disjunctive ray parenchyma end walls indistinct or absent.
Storied structures. Storied structure present, all rays storied, axial parenchyma storied, vessel elements storied, fibres storied. Arrangement of tiers regular (horizontal or straight). Number of ray tiers per axial millimetre 3–4.
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, in other forms, located in ray cells and axial parenchyma cells. Crystal-containing ray cells procumbent. Crystals in procumbent ray cells not in radial alignment. Crystal-containing axial parenchyma cells not chambered. Number of crystals per cell or chamber one and more than one. Crystals in one cell or chamber of the same size. Crystal containing cells of normal size. Cystoliths absent. Navicular crystals in Tabebuia heptaphylla, cubic and navicular crystals in T. serratifolia. Silica not observed.
Physical and chemical tests. Heartwood not fluorescent. Water extract not fluorescent. Water extract basically colourless to brown or shade of brown. Heartwood extractives not leachable by water. Ethanol extract not fluorescent. Ethanol extract basically colourless to brown or shade of brown, or yellow or shade of yellow. Chrome azurol-S test negative. Froth test negative. Splinter burns to charcoal (with very little light grey ash).
Cite this publication as: H. G. Richter and M. J. Dallwitz (2000 onwards). 'Commercial timbers: descriptions, illustrations, identification, and information retrieval.' In English, French, German, and Spanish. Version: 4th May 2000. http://biodiversity.uno.edu/delta/.
Dallwitz (1980) and Dallwitz, Paine and Zurcher (1993 onwards, 1995 onwards, 1998) should also be cited (see General references).