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Nomenclature etc. BORAGINACEAE. Syn.: Gerascanthus glabrata Mart., Lithocardium glabratum Kuntze. Trade and local names: azucarero, japunaqui, picana negra, wira wira negra (BO); claraibeira, louro de-mato-grosso (BR). Not protected under CITES regulations.
Description based on 9 specimens. Tree. Geographic distribution: tropical South America, southern Brazil, temperate South America.
General. Growth ring boundaries distinct (demarcated by marginal parenchyma bands (often discontinuous)). Heartwood basically brown; with streaks. Sapwood colour distinct from heartwood colour. Density 0.8 g/cm³.
Vessels. Wood diffuse porous. Vessels arranged in no specific pattern, in multiples, commonly in short (2–3 vessels) radial rows and in clusters. Average tangential vessel diameter 60–110–140 µm. Average number of vessels/mm² 7. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 5–6 µm. Vessel-ray pits with distinct borders, similar to intervessel pits. Tyloses present, thinwalled. Other deposits present (yellowish brown).
Tracheids and fibres. Fibres of medium wall thickness. Fibre pits mainly restricted to radial walls, simple to minutely bordered.
Axial parenchyma. Axial parenchyma banded. Bands marginal (or seemingly marginal) (bands quite infrequent, apparently marginal). Bands fine. Axial parenchyma apotracheal, or paratracheal. Apotracheal axial parenchyma diffuse and diffuse-in-aggregates. Paratracheal axial parenchyma vasicentric and confluent. Axial parenchyma as strands. Average number of cells per strand: (2–)3–5. Few fusiform parenchyma cells present.
Rays. Rays multiseriate, (2–)4–6 cells wide. 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 or mostly 2–4 marginal rows of upright or square cells. Sheath cells present.
Storied structures. Storied structure absent.
Secretory structures. Intercellular canals absent.
Cambial variants. Included phloem absent.
Mineral inclusions. Crystals present, prismatic, located in ray cells and axial parenchyma cells. Crystal-containing ray cells upright and/or square. 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 and of two distinct sizes. Silica present, as grains; in rays cells and in axial parenchyma. Crystals and silica occur frequently in one and the same cell.
Illustrations. • Macroscopic images. transverse (ca. 10x). radial (natural size). • Transverse section. • Tangential section. • Radial section. • Silica. silica grains in both ray and axial parenchyma cells. • Silica and crystals. silica grains and prismatic crystals occasionally present in one and the same ray cell, a rare coincidence.
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’.
