Commercial Timbers


H. G. Richter and M. J. Dallwitz

Patagonula americana L.(Guajayvi)

Nomenclature etc. BORAGINACEAE. Trade and local names: guajayvi (PY, AR);guaiuvira, guaiabira, guajivira, guarapuvira, guajuvira, guaraiúva, guajuvira-branca (BR). Not protected under CITES regulations.

Tree. Geographic distribution: southern Brazil and temperate South America.

General. Growth ring boundaries distinct. Growth ring boundaries demarcated by fine marginal parenchyma bands and slightly thickened (noded) rays. Heartwood basically brown, with streaks. Sapwood colour distinct from heartwood colour. Odour indistinct or absent. Density 0.7–0.8 g/cm³.

Vessels. Vessels present. Wood diffuse-porous. Vessels arranged in tangential bands, in multiples, commonly short (2–3 vessels) radial rows and in clusters. Vessel outline rounded. Two distinct vessel diameter classes absent. With a tendency towards semi-ringporous. Average tangential vessel diameter 70 µm; diameter of vessel lumina: medium. Average number of vessels/mm² 30–55; vessels per square millimetre moderately numerous and numerous. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 4–6 µm, small, 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, light and dark brown organic contens.

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 present, banded. Axial parenchyma bands marginal (or seemingly marginal), fine, up to three cells wide. Axial parenchyma paratracheal. Paratracheal axial parenchyma vasicentric and confluent. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 2–4(–5). Unlignified parenchyma absent. With some fusiform parenchyma cells.

Rays. Rays present, 4–7 per tangential mm, multiseriate (also if only few), (2–)3–5 cells wide, of medium width (3–5 seriate). Rays with multiseriate portions as wide as uniseriate portions absent. Aggregate rays absent. Rays of one size. Height of large rays 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 and mostly 2–4 marginal rows of upright or square cells. Sheath cells present. 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, in form of crystal sand, located in ray cells, axial parenchyma cells, and fibres. Crystal-containing ray cells upright and/or square and procumbent. Crystal containing cells of normal size. Cystoliths absent. Crystal sand very frequent in marginal ray cells and sheath cells. Silica not observed.

Illustrations. • Transverse section. Patagonula americana. • Tangential section. Patagonula americana. • Radial section. Patagonula americana. • Crystal sand in ray cells. Patagonula americana. Microcrystals (crystal sand) in rays: procumbent, upright and sheath cells.

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.’.