126 MOTIONS OF TEEES. 



like the American elm, wave their branches gracefully, 

 with but little apparent motion of their leaves. We ob- 

 serve the same habit ia the weepiag willow, and indeed 

 in all trees with a long and flexible spray. The wind 

 produces by its action on these a general sweeping move- 

 ment without any rustle. It is easy to observe, when 

 walking in a grove, that the only graceful motions come 

 from trees with drooping branches, because these alone 

 are long and slender. 



The very rapid motion of the leaves of the aspen has 

 given origin to some remarkable superstitions. The 

 Highlanders of Scotland believe the wood of this tree to 

 be that of which the holy cross was made, and that its 

 leaves are consequently never allowed to rest. Impressed 

 with the awfulness of the tragedy of the crucifixion, they 

 are constantly indicating to the wiads the terrors that 

 agitate them. The small white birch displays consider- 

 able of the same motion of the leaves ; but we take little 

 notice of it, because they are softer and produce less 

 of a rustling sound. The flickering lights and shadows 

 observed when walking under these trees, on a bright 

 noonday, have always been admired. All these habits 

 awaken our interest in trees and other plants by assimi- 

 lating them to animated things. 



Much of the beauty-of the silver poplar comes from 

 its glittering lights, when it presents the green upper 

 surface of its foliage, alternating rapidly with the white 

 silvery surface beneath. This we may readily perceive 

 even in cloudy weather, but in the bright sunshine the 

 contrasts are very brilliant. In all trees, however, we 

 observe this glittering beauty of motion in the sun- 

 shine. The under part of leaves being less glossy than 

 the upper part, there is in the assemblage the same 

 tremulous lustre that appears on the rippled surface of a 

 lake by moonlight. 



