| | Commercial timbers |
Nomenclature etc. PAULOWNIACEAE (SCROPHULARIACEAE). Syn.: Paulownia imperialis Sieb. & Zucc. Trade and local names: kiri, shima-giri (JP); Paulownia (trade); mao pao tong (CN); paulownia impérial (FR); empresstree (GB, US); chinesischer Blauglockenbaum (DE). Not protected under CITES regulations.
Tree. Geographic distribution: temperate Asia (cultivated worldwide in temperate and subtropical climate regions).
General. Growth ring boundaries distinct. Heartwood basically white or grey. Sapwood colour similar to heartwood colour. Density 0.25–0.3 g/cm³.
Vessels. Vessels present. Wood ring porous or semi ring porous. Vessels arranged in no specific pattern, in multiples, commonly in short (2–3 vessels) radial rows or in clusters (latewood). Average tangential vessel diameter 200–300 µm (earlywood). Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 6–8 µm. Vessel-ray pits with distinct borders or with reduced borders or apparently simple, similar to intervessel pits or different from intervessel pits, rounded or angular. Helical thickenings present, only in narrow vessel elements, throughout the body of vessel elements. Tyloses present, thinwalled.
Tracheids and fibres. Fibres very thin-walled. Fibre pits mainly restricted to radial walls, simple to minutely bordered.
Axial parenchyma. Axial parenchyma present, banded or not banded. Bands marginal (or seemingly marginal). Bands coarse (intial parenchyma as wide as the earlywood pore ring). Axial parenchyma apotracheal, or paratracheal. Apotracheal axial parenchyma diffuse-in-aggregates. Paratracheal axial parenchyma vasicentric, or aliform, or confluent (latewood vessles only). Aliform parenchyma of the lozenge type and of the winged type. Axial parenchyma as strands. Average number of cells per strand: 2–5.
Rays. Rays 3–6 per tangential mm, multiseriate, 2–5 cells wide. Height of large rays up to 500 µm. Rays composed of a single cell type (homocellular), or two or more cell types (heterocellular); homocellular ray cells procumbent. Heterocellular rays with square and upright cells restricted to marginal rows, mostly 1 marginal row of upright or square cells.
Secretory structures. Intercellular canals absent.
Mineral inclusions. Crystals not observed. Silica not observed.
Physical and chemical tests. Heartwood not fluorescent. Water extract not fluorescent; colour of water extract colourless to brown. Ethanol extract not fluorescent. Colour of ethanol extract colourless to brown. Splinter burns to partial ash. Ash white to grey.
Illustrations. • Macroscopic images: cross section. transverse (ca. 10x). • Macroscopic images: wood surface. surface (natural size). tangential. radial. • Transverse section. • Tangential section. • Radial section.
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’.
