Commercial Timbers


H. G. Richter and M. J. Dallwitz

Cryptocarya spp. Tropical Asia (Medang)

Nomenclature etc. LAURACEAE. Description based on approximately 30 species from tropical Asia and the australo-pacific region. Trade and local names: medang (trade); cryptocarya (PG); dugkatan, manayau (PH).

Description based on 40 (specimens). Tree. Geographic distribution: Indomalesia, Australia, and southern Brazil.

General. Growth ring boundaries distinct and indistinct or absent. Growth ring limits demarcated by marginal parenchyma bands, not in all instances distinct. Heartwood basically brown white or grey, without streaks. Sapwood colour similar to heartwood colour, or distinct from heartwood colour. Odour distinct, or indistinct or absent. Density 0.55–0.77 g/cm³. Wood of commercial potential.

Vessels. Vessels present. Wood diffuse-porous. Vessels arranged in no specific 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. Average tangential vessel diameter 60–170(–230) µm; diameter of vessel lumina: large. Average number of vessels/mm² (5–)9–12; vessels per square millimetre few. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) (8–)10–14 µm, medium and large, not vestured. Vessel-ray pits with reduced borders or apparently simple, rounded or angular and horizontal to vertical, of uniform size or type, of the same type in adjacent elements, located throughout the ray. Helical thickenings absent. Tyloses in vessels present, thinwalled and sclerotic. Other deposits in heartwood vessels not observed, tyloses partly sclerotic in C.nitens.

Tracheids and fibres. Vascular or vasicentric tracheids sporadic to absent. Fibres of medium wall thickness. Average fibre length (700–)1000–1400(–1600) 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), fine, up to three cells wide and coarse, more than three cells wide. Axial parenchyma paratracheal. Paratracheal axial parenchyma vasicentric. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 2–4(–8). Unlignified parenchyma absent.

Rays. Rays present, 5–8 per tangential mm, multiseriate (also if only few), (1–)2–4(–6) cells wide, narrow (2–3 seriate) and of medium width (3–5 seriate). Rays with multiseriate portions as wide as uniseriate portions absent. Aggregate rays present, or absent. Rays of two distinct sizes, or of one size. Height of large rays up to 500 µm and 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 absent. Tile cells absent. Perforated ray cells absent. Disjunctive ray parenchyma end walls indistinct or absent. (Aggregate rays observed in C. chinensis, C. corrugata, C. glaucescens, C. meissneri) aggregate rays observed in C. chinensis, C. corrugata, C. glaucescens, C. meissneri.

Storied structures. Storied structure absent.

Secretory structures. Oil and mucilage cells present, associated with axial parenchyma and ray parenchyma (in rays only sporadically). Intercellular canals absent. Laticifers or tanniniferous tubes absent.

Cambial variants. Included phloem absent. Other cambial variants absent.

Mineral inclusions. Crystals present and not observed, in other forms, located in ray cells. Crystal-containing ray cells upright and/or square and procumbent, upright and/or square ray cells not chambered. Crystals in procumbent ray cells not in radial alignment. Number of crystals per cell or chamber more than one. Crystals in one cell or chamber of the same size. Crystal containing cells of normal size. Cystoliths absent. Crystals usually small (isodiametric, rod-like, acicular) and observed in: C. crassinervia, C. ferrea, C. membranaceae, C. multipaniculata, C. nitens, C. tomentosa, C. triplinervis, C. vulgaris. Silica present or not observed, as grains and in aggregates, in rays cells. Silica observed in: C. aristata, C. corrugata, C. gigantocarpa, C. glaucescens, C. invasorium, C. leptospermoides, C. odorata, C. pluricostata, C. transversa..

Physical and chemical tests. Heartwood not fluorescent. Water extract not fluorescent; basically colourless to brown or shade of brown. Heartwood extractives not leachable by water. Ethanol extract not fluorescent. Colour of ethanol extract colourless to brown or shade of brown. Chrome azurol-S test negative. Froth test positive. Splinter burns to partial ash. Ash yellow-brown.

Illustrations. • Transverse section. Cryptocarya cunninghamii. (Vessels mostly solitary). Cryptocarya densiflora. (Vessels mostly in radial groups). • Transverse section enlarged. Cryprocarya ferrea. (marginal band and paratracheal parenchyma, numerous oil cells). • Tangential section. Cryptocarya ferrea. • Radial section. Cryptocarya oblata. • Vessel and fibre pits. Cryptocarya massoy. (large alternate intervessel pitting). Cryptocarya odorata. (numerous prominent fibre pits in radial walls. • Oil cells. Cryptocarya pluricostata. (numerous large oil cells associated with axial parenchyma and/or fibres). radial. tangential. Cryptocarya oblata. (oil cells associated with axial parenchyma and rarely with rays). radial. • Crystals and silica. Cryptocarya mackinnoniana. (numerous small crystals in ray cells - 1/2 polarized). Cryptocarya leptospermoides. (irregular silica particles in ray 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.’.