POPLARS 187 



cannot lead to mistakes if the leaves and buds are com- 

 pared. 



Tall trees, over 40 50 feet in height. 



$ Bark grey -whitish or greyish-green, [For 



tending to scale. Buds with several see P'188.] 

 scales. Crown rounded, the stem 

 traceable through it; branches off at 

 acute angles, but some bend over; 

 twigs thin and rather whippy. 

 Foliage broad, white below. Flowers 

 in catkins; fruit capsular ; seeds 

 minute comose. 



Popidus alba, L. Abele (Fig. 88). Round-headed 

 tree, 60 90 feet high, with the pale grey limbs and trunk 

 which remain smooth for a long time, and then acquire 

 fissures and broad ridges tending to break up into scales 

 on old boles. The crown is ovoid-conic to rounded, pro- 

 viding medium curve as the branching is rather loose. 

 Foliage of broad leaves, very white-cottony beneath, as 

 is especially evident when they are upturned by wind. 

 Twigs long and slender, grey-white and cottony. 



Populus tremula, L. Aspen. This tree can only be 

 distinguished from P. alba and the variety P. cinerea 

 by details of the leaves and flowers (see Vols. II. IV.), 

 but it is usually a smaller tree with yellower and smooth, 

 not cottony, twigs, and somewhat larger buds ; and the 

 leaves are more rounded and on longer petioles to which 

 the trembling is due. Both species have a great tendency 

 to throw up suckers. Crown broadly rounded, loose. 



There are but few trees with the leaves white beneath 

 (see Pyrus Mains, P. Aria and P. torminalis, pp. 197 9). 



The two Willows, Salix alba and S. fragilis, the 

 former of which has silky white leaves and shoots, and 

 both of which may be greyish, are at once distinguished 



