COTTONWOOD 



glow in still air. " Burns badly, and needs much draught " (87). 



Grain. Extremely fine though open. Surface lustrous. 



Bark. Blackish, deeply fissured, persistent. 



Uses, etc. " Carving, carpentry, paper-pulp, railway break- 

 blocks, clogs, packing-cases, etc. . . . not durable " (113). 



Authorities. Nordlinger (87), p. 530. Ditto (86), vol. iii. 

 p. 57. Westermeier (129), p. 38. Du Mornay (70), p. 85. Steven- 

 son (113), p. 92. Laslett (60), p. 165. Schwartz (106), p. 486. 

 Boulger (12). Wiesner (113), L. 12, p. 882. Mathieu(6g), p. 492. 



This wood is frequently confused with other species of Poplar, 

 with Cotton-wood, Canary White-wood and other light soft 

 woods. 



Colour. Whitish : light brown : brownish-grey heart-wood 

 with whitish or yellowish-white sap-wood, which is from 8-20 

 rings wide. " Veined with black in the heart " (69). 



Anatomical Characters. Transverse section : — 



Pores. Need lens, rather fine, size 4, varying considerably : 

 uniformly scattered but branched in wide rings or arranged in 

 loose festoons : numerous, 75-90 per sq. mm. : single or in sub- 

 divided radial groups of 2-8 : oval : empty. 



Rays. Just visible, very fine, size 6, uniform : equidistant, 

 about the width of a large pore apart : nearly straight, running 

 round the larger pores at times : denser than the ground-tissue : 

 very numerous, 10-13 per mm. : almost the same colour as the 

 ground. 



Rings. Distinct, though not prominent : boundary, a clear, 

 fine line of Autumn wood : contour regular. 



Sop-tissue. Single cells or irregular areas apparently the bulk 

 of the tissue. 



Pith. About 1 mm. wide, five-sided to round : greenish- 

 white (green in the angles). 



Radial Section. Pores fine, shining, empty lines, with 

 chambers longer than the width of the groove. Rays just visible 

 in certain lights : fine, colourless, shining flakes. Ring-bound- 

 aries very fine lines, scarcely traceable. 



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

 unless when stained, fine lines about o - 5 mm. high, and the 

 ring-boundaries are readily traceable, distinct, fine lines. 



Type specimens from commercial sources and also from trees 

 known before felling. 



No. 208. COTTONWOOD. Probably Populus monili- 



fera. Ait. 



Plate XV. As Fig. 130. 

 Natural Order. Salicinese. 



237 



