Mountain ash 



Pores. Need lens, fine, size 5, little variation : evenly 

 distributed in groups of from 2-5 occupying the whole ring : 

 very numerous, 100-200 per sq. mm. 



Rays. Need lens, fine to medium, size 4-5 : somewhat irregu- 

 larly spaced, a pore-width or more apart : not long : slightly 

 undulating, tapering gently at both ends : little if any denser 

 than the ground-tissue : difficult to see in a transparent section : 

 very numerous, 6-8 per mm. : " 10-13 " ( X 3 Z ) '• weak or waved, 

 but scarcely avoiding the pores. 



Rings. Very clear : the boundary a fine clear line of dense 

 Autumn wood : contour undulating. 



Soft-tissue. In occasional isolated cells or lines. 



Pith. Small, 1-3 mm. diameter, round or lobed, nearly as 

 hard as the wood. 



Radial Section. Pores minute, colourless lines sometimes 

 shining. Rays, minute flakes slightly darker than the ground- 

 tissue. Rings clear but the very fine boundary lines a little 

 darker than the remainder of the ring. 



Tangential Section. As the Radial, but the rays are minute, 

 almost imperceptible vertical lines ; about 0.5 mm. high. 



Type specimens from commercial sources and also from trees 

 known before felling. 



No. 90. MOUNTAIN ASH. Pyrus aucuparia. 



Ehrh. 



Plate VII. Fig. 59. 



Natural Order. Rosacese. 



Synonyms. Sorbus aucuparia. Linn. (Pirus = Pyrus). 

 Alternative Names. Rowan tree : Fowler's Service Tree : 

 Quicken Tree. Cochene : Sorbier des Oiseaux (69). Eberesche 



(87). 



Sources of Supply. Europe : Madeira : N. and W. Asia : 

 N. America. 



Physical Characters, etc. Recorded dry-weight 35J— 48J lbs; 

 per cu. ft. Hardness Grade 6, compare Beech or Apple. Smell 

 or taste little if any. Burns well : embers glow in still air. Solu- 

 tion with water or alcohol colourless. 



Grain. Extremely fine, close and dense. Surface bright : 

 " Satine " (69). 



Bark. Reddish-brown, smooth, shining. Grey later, shining 

 only here and there where the original epidermis remains. 



Uses, etc. " Turnery, tools, frictional parts of machines " 

 (69). "Wood-engraving, tools especially screw, for presses" 

 (70). "Furniture, turnery and carving : flexible: not durable" 

 (129). Splits unevenly and with difficulty. 



105 



