328 



THE NATURE BOOK 



an almost snowy appearance in contrast 

 with the greener}' ot other trees. 



The bark is the greenish grey so charac- 

 teristic of the smooth Poplar bark ; but 

 this tint, and the attendant smoothness, 

 are with the White Poplar more pro- 

 nounced, and longer retained, than with 

 its allies. The lozenge-shaped breathing 

 apertures in its smooth grey surface are 

 numerous and very noticeable. Not until 

 the tree is well matured docs the bark 

 at the base commence to roughen. The 

 new shoots and 3'oung leaves are covered 

 with a white cottony down, as if smothered 

 with roadside motor-dust. This down 

 easily rubs off. Remains of it are never- 

 theless found in the ivintcr twigs, giving 

 to their natural ohve brown colour a 

 greenish grey appearance. The resting 

 buds are spirally arranged on the twigs, 



TKUNK OI-" WllME I'Ol'LAK. 

 Showing both smooth and rough bark. 



and are shorter and less 

 pointed than those of the 

 Aspen, not sticky, but 

 covered with cottony down 

 as are the twigs. The cat- 

 kin buds are larger and more 

 rounded. The leaves when 

 mature are thick and tough, 

 deep green and smooth 

 above, with the under sur- 

 face so thickly crowded with 

 white hairs as to give the 

 appearance of white felt ; 

 they are also felt-like to the 

 touch. In shape they are 

 more than usually variable. 

 They may be almost heart- 

 shaped with sinuous outline ; 

 or rounded, or long oval, 

 \\ ith blunt teeth ; or cut 

 into, forming three or five 

 distinct divisions, as is gener- 

 ally the case with those 

 growing on the very numer- 

 ous suckers. The leaf-stalks 

 are shorter than those of the 

 Aspen, very little flattened, 

 and the leaves are carried 

 more horizontally. The cat- 

 kins of pollen-bearing flowers 

 are very slightly hairy, those 

 of fruit-producing flowers not 

 at all. These last are green 

 in colour. 



THE GREY POPLAR 



The Grey Poj)lar combines 

 more or less the character- 

 istics of the Aspen and the 

 White Poplar. In 

 habit of growth it is 

 \'ery similar to the 

 latter tree, but its 

 twigs and buds are 

 less hairy. Yet its buds are not sticky like 

 those of the Aspen. The leaf-stalks are 

 rather more flattened than those of the 

 White Po})lar. The leaves are more like 

 the Asi)en's in shape, but lighter in colour 

 and hairy on the under surface, though 

 less so than those of the White Poplar. 



THE BLACK POPLAR 



This tree is black in the sense only that 

 it is not white, being so namel in dis- 

 tinction from the White Poplar. It is 



WINTER TWIG AND 

 RESTING BUD 

 (ENLARGED) OF 

 WHITE POPLAR. 



