THE AMERICAN BOTANIST. 
5 
Although leaves have not the power of self-utterance, 
yet are they played upon by the winds, so that, according 
to Nature's whim they give rise to softest whispers, sooth- 
ing lullabies, sublime symphonies, or the harmonious crash 
of opera or oratorio. Most melodious of these aeolian harps 
are the needles of the pine, singing ever ''in accents discon- 
solate", and simulating the ocean's surge. 
'*As sings the pine tree in the wind. 
So sings in the wind, a sprig of the pine", 
How often we long to interpret this music ! 
Apart from these sounds, however, or the whistle of 
sedges along a marshy shore, or the dry rattle of oak leaves 
persisting throughout the bleak winter, we think of leaves as 
quiescent, or only moving through the impact of a breeze. 
Some, indeed, like those of aspen or birch, "palpitate for- 
ever", but the pulsing is due to external causes. 
Much as one may love a tree, we cannot attribute 
consciousness to it, though some recent authors appear to 
think that way. The strange movements we may 
note, and of some of which we shall here speak, can be 
explained on purely mechanical principles — unequal tension 
of tissues, or fluids in unstable equilibrium. In aspens and 
poplars generally the leaf-stalk is flattened contrary to the 
plane of the blade, and therefore catches every passing 
breeze, transmitting the motion to the blade. Rarely do 
we observe such leaves at rest. They have become symbolic 
of fickleness. 
"O woman, in our hours of ease. 
Uncertain, coy, and hard to please, 
And variable as the shade 
By the light, quivering aspen made". 
It has been suggested that the motion imparted to leaves by 
the wind aids them in their special functions as organs of 
evaporation and assimilation. 
