SILKY OAK 



No. 162. SILKY OAK. Grevillea robusta. A. Cunn. 

 Plate XII. Fig. 102. 



Natural Order. Proteacese. 



Synonyms. G. venusta. A. Cunn. G. Umbratica. A. Cunn. 



Alternative Names. Tuggan-tuggan (5). Warra-garria. Koom- 

 kabang (120). Grevillea (49). 



Sources of Supply. South Queensland, New South Wales. 



Physical Characters, etc. Dry-weight about 37£lbs. per cu. ft. 

 Boulger gives the weight per cu. ft. as 35'25-38 - 8 lbs. and the 

 specific gravity as '564 only, thus making it appear that the 

 weight varies while the specific gravity does not. Smell and 

 taste none. Hardness Grade 6, compare Beech. Burns very 

 well, ignites readily : embers glow in still air : heat expels a 

 yellowish juice. Solution with water colourless. 



Grain. Of medium coarseness, open and even. Surface 

 lustrous or silky, the rays dull. 



Bark. "Rugged" (5). 



Uses, etc. " Elastic and durable " (131). " Staves for tallow- 

 casks, cabinet-work " (5). " Interior-work, . . . becoming 

 scarce " " May be met with in logs of 50-100 feet in length by 

 even as much as 6-8 ft. in diameter " (111). 



Authorities. F. M. Bailey (5), p. 117. Laslett (60), p. 255. 

 J. Smith (in), p. 379. Nilson (85), p. 85. Wiesner (131), 

 L. p. 70. Timber Trades Journal (120), June 6, 1903, p. 998. 

 Hough (49), pt. ix. p. 35. 



Colour. Pinkish to light-brown. 



Anatomical Characters. Transverse section : — 



Pores. Very clear, size 2, medium, uniform : evenly distri- 

 buted in concave loops between the rays (dentate) : a pore-ring 

 of one or at most two rows : no pores in the later wood : isolated 

 or in subdivided clusters of from 3-5 ; few, 5-12 per mm. : 

 accompanied by a line of brown soft-tissue : round or if oval the 

 long axis tangential : amber or ruby contents. 



Rays. Conspicuous : size 2-3, apparently compound and 

 of two sizes. Large ones fairly equidistant, rarely less than 

 1 mm. apart : straight and direct : nodose at long intervals : 

 very lax yet denser than the ground : marked transversely with 

 fine bars. Small rays avoid the pores : straggling, following the 

 contour of the nodes of the larger when close to them : bright, 

 light brown. 



Rings. Clear and distinctly visible though fine : boundary 

 the pore-ring and its loops : contour finely dentate. 



Soft-tissue. Abundant in concentric lines following the pore- 

 rings : joining the pores : size about 4 : cells extended in a 

 tangential direction, rectangular but minute : brown. 



185 



