LABURNUM G.N. 1638 



LABURNUM 



Laburnum anagyroides Medic.: synonyms, Laburnum vulgare J. Presl.; 

 Cytisus Laburnum Linn. Leguminosae (Papilionatse). 



A hard, heavy wood of a greenish to deep brown colour, sometimes 

 almost black. Generally in small pieces. Lustre satiny. Structure clear. 

 A heartwood tree. Sapwood narrow, of 2-5 rings only. 



Transverse section. Boundary, the pore-ring of about three rows of 

 small pores compacted by parenchyma. Parenchyma vaaicentric 

 (sheathing the vessels) and joining them up to oblique lines that 

 sometimes form crosses, angles and even lines. The latter flatten out 

 much in the Autumn wood. Vessels small, not individually visible: 

 those of the pore-ring not much larger than those in the later wood 

 external to it: diminishing regularly outwards towards the boundary 

 and nearly always linked up to others by parenchyma. Thyloses few 

 and not very evident. Rays just visible at arm's length, though fine: 

 irregular in size and spacing, at intervals of 3-4 times the width of a pore: 

 colour, white, yellow or brown. 



Radial section. Boundaries, conspicuous as lines of vessels accompanied 

 by parenchyma of a lighter colour. Rays inconspicuous but quite evident, 

 narrow flakes. 



Tangential section. As the radial, but the boundaries are loops with 

 conspicuous fringes and bands and patches of parenchyma. A zigzag 

 tracery within the loops in the Autumn wood. Under the microscope 

 the parenchyma is seen to be in palisade and the rays are high in 

 proportion of those of Robinia : the highest are equal to that of about 

 30 parenchyma-cells of the same wood. 



May be confused with: May be distinguished by: 



Robinia (thyloses very abundant, Rays high in tangential section, 



the vessels being packed with them: thyloses rare; silver-grain though 



rays low in tangential section whitish, darkens to brown on ex- 



( microscope) : silver-grain and posure. 

 parenchyma remain white while the 

 fibres deepen in colour). 



Mulberry (parenchyma-cells Parenchyma-cells in palisade, 

 alternate). 



Elms (pores of the pore-ring Pores of the pore-ring scam-lv 



much larger than those of the later larger than those following on: 



wood: parenchyma-cells alternate), parenchyma-cells in palisade in 



vertical section (microscope). 



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