Commercial Timbers


H. G. Richter and M. J. Dallwitz

Sideroxylon obtusifolium (Roem. & Schult.) Penn. (Yvyra hu)

Nomenclature etc. SAPOTACEAE. Syn.: Bumelia obtusifolia Roem. et Schult. Trade and local names: yvyra hu, yvyra jepoka (PY); ibira-niná, guaraniná, palo de lanza, horco molle, palo piedra(AR). Not protected under CITES regulations.

Description based on 4 specimens. Tree. Geographic distribution: southern Brazil and temperate South America.

General. Growth ring boundaries indistinct or absent. Heartwood basically yellow, without streaks. Sapwood colour similar to heartwood colour. Density 0.75–0.8 g/cm³.

Vessels. Vessels present. Wood diffuse-porous. Vessels arranged in diagonal and/or radial pattern and dendritic pattern, in multiples, commonly short (2–3 vessels) radial rows and radial rows of 4 or more. Vessel outline rounded. Two distinct vessel diameter classes absent. The dendritic distribution pattern of the vessels is not particularly conspicuous. Average tangential vessel diameter 30–60–75 µm; diameter of vessel lumina: medium. Average number of vessels/mm² 35–55; vessels per square millimetre moderately numerous and numerous. Average vessel element length 364 µm. Average vessel element length medium. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 4–6 µm, small, not vestured. Vessel-ray pits with distinct borders and with reduced borders or apparently simple, similar to intervessel pits and different from intervessel pits, rounded or angular and horizontal to vertical, of two distinct sizes or types in the same ray cell, of the same type in adjacent elements, located throughout the ray. Helical thickenings absent. Tyloses in vessels absent. Other deposits in heartwood vessels not observed.

Tracheids and fibres. Vascular or vasicentric tracheids commonly present. Fibres very thick-walled. Average fibre length 1000 µm. Average fibre length medium. 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), bands much wider than rays, fine, up to three cells wide and coarse, more than three cells wide, 3–5 per radial mm. Fine Parenchyma bands (up to 3 celles wide) both of the marginal and non-marginal type. Axial parenchyma apotracheal. Apotracheal axial parenchyma diffuse-in-aggregates. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 3–6(–8). Unlignified parenchyma absent.

Rays. Rays present, 10–15 per tangential mm, multiseriate (also if only few), 2–3(–4) cells wide, narrow (2–3 seriate). 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 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 absent. Tile cells absent. Perforated ray cells absent. Disjunctive ray parenchyma end walls distinct. Rays rarely with 2–4 marginal cell rows.

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 and axial parenchyma cells. Crystal-containing ray cells upright and/or square. Cystoliths absent. Silica not observed.

Illustrations. • Transverse section1. Sideroxylon obtusifolium. • Transverse section2. Sideroxylon obtusifolium. • Tangential section. Sideroxylon obtusifolium. • Radial section. Sideroxylon obtusifolium. • Crystal sand in axial parenchyma. Sideroxylon obtusifolium. Micro crystals (crystal sand) in axial parenchyma cells under normal (left) and polarized (right) light.

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.’.