Commercial Timbers


H. G. Richter and M. J. Dallwitz

Cercidiphyllum japonicum (Sieb. & Zucc.) (Katsura)

Nomenclature etc. CERCIDIPHYLLACEAE. Trade and local names: katsura (JP). Not protected under CITES regulations.

Description based on 2 specimens. Tree. Geographic distribution: temperate Asia.

General. Growth ring boundaries distinct. Growthring limits marked by radially flattened fibres. Heartwood basically brown, without streaks. Sapwood colour distinct from heartwood colour. Odour indistinct or absent. Density 0.42–0.48 g/cm³.

Vessels. Vessels present. Wood diffuse-porous. Vessels arranged in no specific pattern, in multiples, commonly short (2–3 vessels) radial rows and in clusters. Vessel outline rounded and angular. Two distinct vessel diameter classes absent. Average tangential vessel diameter 40–60–70 µm; diameter of vessel lumina: medium. Average number of vessels/mm² 140–190; vessels per square millimetre very numerous. Perforation plates scalariform, with 20–35 bars. Intervessel pits scalariform, average diameter (vertical) 5–7 µm, small, not vestured. Vessel-ray pits with distinct borders and with reduced borders or apparently simple, similar to intervessel pits, horizontal to vertical, of uniform size or type, of the same type in adjacent elements, restricted to marginal rows. Helical thickenings present, in narrow and wide vessel elements, only in vessel element tails. Tyloses in vessels present, thinwalled. Other deposits in heartwood vessels not observed.

Tracheids and fibres. Vascular or vasicentric tracheids sporadic to absent. Fibres very thin-walled. Fibre pits common in both radial and tangential walls, distinctly bordered. Helical thickenings absent. Fibres non-septate.

Axial parenchyma. Axial parenchyma present, not banded. Axial parenchyma apotracheal and paratracheal. Apotracheal axial parenchyma diffuse and diffuse-in-aggregates. Paratracheal axial parenchyma scanty. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 6–9. Unlignified parenchyma absent.

Rays. Rays present, 7–10 per tangential mm, multiseriate (also if only few), 1–2 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 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 not observed. Silica not observed.

Physical and chemical tests. Heartwood not fluorescent. Water extract 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. Water extract weakly fluorescent. Chrome azurol-S test negative. Froth test negative. Splinter burns to charcoal.

Illustrations. • Transverse section. Cercidiphyllum japonicum. • Tangential section. Cercidiphyllum japonicum. Note: Long and steeply inclined scalariform perforation plates (left). • Radial section. Cercidiphyllum japonicum. Note: Scalariform perforation plate (left). • Radial section detail. Cercidiphyllum japonicum. Note: Details of ray composition, horizontal ray-vessel pitting, scalariform perforation plates, tyloses. • Helical thickenings in vessel tips. Cercidiphyllum japonicum. Note: Helical thickenings only in vessel element tails (not in all specimens observed).

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.’.