FALSE ACACIA O.N. 1691 



FALSE ACACIA 



Robinia Pseudo-Acacia Linn. Leguminosae (Papilionatae). 



A hard, heavy wood of a whitish-greenish brown colour to dark brown 

 streaked with pale lines : ring-porous with frequently a prominent zigzag 

 tracery in tangential section. Structure particularly clear in transverse 

 section where the fibres are very dense and take a sort of natural polish 

 from the tool. Lustre in longitudinal section often metallic. A very 

 variable wood. A heartwood tree. Sapwood narrow, from 1-5 rings 

 only. 



Transverse section. Boundary, the scanty pore-ring compacted and 

 rendered evident and often conspicuous, by much light-coloured paren- 

 chyma. Contour sub-regular. 



Parenchyma as above, but in the dense, well-grown wood, confined 

 to small amounts around or attached to the vessels (i.e. vasicentric) : 

 in the outer zone of the late wood, sometimes joining up a few groups of 

 pores to short lines and angles or even running to concentric lines. Colour 

 of the parenchyma, white or greenish-white : it remains so after the wood 

 has been darkened by exposure. 



Vessels small yet individually visible, diminishing a little and regularly 

 outwards to the boundary. Excepting those of the pore-ring, they are 

 widely isolated radially (i.e. the groups, which may be of from one to 

 three, or even more vessels). The vessels of the pore-ring are scarcely 

 larger than those produced immediately after. All are choked with 

 thyloses which are visible with the lens. 



(Obs. In some cases all the pores are connected into concentric lines; 

 see the 4-ft plank No. 279/1691.) 



Rays visible at arm's length, irregular in size and spacing, at intervals 

 of the width of a pore or less. They appear at times to run through the 

 edges of the vessels, but in reality they pass through their sheaths of 

 parenchyma (a). Colour of rays, white, yellow or brown. 



Radial section. Boundary conspicuous as a band of coarse vessels 

 along which the parenchyma (a) appears as a prominent, hoary stripe. 

 Rays dull and inconspicuous though fairly large hoary or white flakes. 



Tangential section. As the radial, but the boundaries are very con- 

 spicuous coarsely-fringed loops with broad patches of dull, hoary 

 parenchyma. Under the microscope the rays are seen to be low (the 

 highest equal to about the length of ten of the parenchyma cells of 

 same wood), in comparison with those of the Laburnum and are in 

 palisade as in that species (see Fig. 12). 



Reaction of perchloride of iron upon the watery extract, inky. 



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