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Nomenclature etc. FABACEAE-FABOIDEAE. Species included in the description: Hymenolobium elatum Ducke (1), Hymenolobium excelsum Ducke (2), Hymenolobium flavum Kleinh. (2), Hymenolobium petraeum Ducke (3). Trade and local names: angelim amarelo, a. aroeira, a. do Pará, mirarema, sucupira (sapupira) amarela (BR); koraroballi (GY); makkakapes, saandoe (SM); saint Martin jaune (GF);. Not protected under CITES regulations.
Description based on 8 specimens. Tree. Geographic distribution: tropical South America.
General. Heartwood basically brown and yellow; with streaks. Sapwood colour distinct from heartwood colour. Density 0.7–0.85 g/cm³.
Vessels. Wood diffuse porous. Vessels arranged in no specific pattern, in multiples, commonly in short (2–3 vessels) radial rows or in radial rows of 4 or more (few). Vessels often with radial multi-vessel tails. Average tangential vessel diameter 135–230–325 µm. Vessels per square millimetre very few. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 6–10 µm, pits vestured. Vessel-ray pits with distinct borders, similar to intervessel pits. Other deposits present, brown to black deposits.
Tracheids and fibres. Fibres very thick-walled. Fibre pits mainly restricted to radial walls, simple to minutely bordered. Fibres non-septate.
Axial parenchyma. Axial parenchyma banded. Bands not marginal (or seemingly marginal). Axial parenchyma bands much wider than rays. Bands coarse. Banded parenchyma less developed in H. excelsum. Axial parenchyma apotracheal, or paratracheal. Apotracheal axial parenchyma diffuse-in-aggregates. Paratracheal axial parenchyma aliform and confluent. Aliform parenchyma of the lozenge type. Axial parenchyma as strands. Average number of cells per strand: 4(–5).
Rays. Rays multiseriate, 2–3–5 cells wide. 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. Wood rays 2–3 cells wide in H.elatum, H. flavum and H. petraeum; 3–5 cells wide in H.excelsum.
Storied structures. Storied structure present, all rays storied, axial parenchyma storied, vessel elements storied and not storied, fibres not storied. Arrangement of tiers regular, or irregular. Number of ray tiers per axial millimetre 2. Storied structure (rays) less obvious in H. flavum.
Secretory structures. Intercellular canals absent.
Cambial variants. Included phloem 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. Silica not observed.
Physical and chemical tests. Heartwood fluorescent (yellow). Water extract fluorescent; colour of water extract colourless to brown. Ethanol extract fluorescent. Colour of ethanol extract red. Water extract with yellow, ethanol extract with whitish fluorescence. Splinter burns to partial ash. Ash bright white.
Illustrations. • Transverse section. Hymenolobium petraeum. • Tangential section 1. Hymenolobium petraeum. specimen with irregularly storied rays. • Tangential section 2. Hymenolobium petraeum. specimen with neatly storied rays. • Radial section. Hymenolobium petraeum.
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’.
