86 ON SOME RESEMBLANCES BETWEEN PLANTS AND. ANIMALS. 
One of the most extraordinary instances of spontaneous move- 
ment in a plant is seen in the leaves of Desmodium gyrans, a 
leguminous plant. The leaves have three leaflets, and the two 
side leaflets are always gently moving up and down, quite 
irrespective of any currents of air. 3 
And now I will just give you a veritable instance or two of 
locomotion in plants—the power of moving from place to place. 
The first is seen in the beautiful Orchises that give our 
meadows such a charming appearance in the early summer. 
The bulbs of these plants differ somewhat from many bulbs, 
inasmuch as they die away every year, the flower spike feeding 
on the starch of the bulb; but while the Orchis is growing a new 
bulb is being formed, at one side of the old one, and thus the plant 
comes up each year perhaps half an inch from the place where it 
came up last year, and so, in the course of time, Orchises change 
their position considerably. 
But this, I must own, is somewhat different from locomotion in 
animals, and is only similar in its effects. There are, however, 
certain parts of low plants that really do move about from place 
to place. Connected with the organs of fructification of many low 
water plants, there are exceedingly minute bodies, called 
‘« zoospores,” only visible with the microscope. These bodies 
have delicate hairs attached to them, which move freely about 
and propel the zoospore through the water for some time after it 
is detached from the parent plant. 
Plants resemble animals in resting at stated periods. The 
closing of leaves and flowers at night is called the sleep of plants ; 
but I should be inclined to look upon it rather as a means of 
protection to delicate organs, than as a time of rest for the plant. 
But hybernation, the quiescence of trees during winter—though 
depending, partly at any rate, on external cireumstances—really 
acts like sleep to.an animal, and enables the plant to start with 
fresh vigour, when the genial spring sunshine calls it to life, 
and sends the sap up again to the old branches. 
There are very many curious facts with regard to the sleep of 
plants, the periodicity of their opening, and the curious ways they 
