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their periods of sleep become extremely irregular for a 
time, but, in the end, the specimens generally close 
their leaves during the day, and unfold them at night. 
The alternate opening and closing of flowers is a 
similar fonction to that of the sleep of leaves. The 
time of day in which flowers close is very different 
for different species, and even differs for that period 
during which the leaves are asleep on the very same 
plant. Bertholet mentions an Acacia in the garden of 
Orotava, in Teneriffe, whose leaflets closed at sunset 
and unfolded at sunrise, whilst its flowers closed at 
sunrise and expanded at sunset.” 
Having given the botanist’s account of this re- 
markable property, we will allow the poet to tell his 
opinion. 
“ The flower, enamoured of the sun, 
At his departure hangs her head and weeps, 
And shrouds her sweetness up, and keeps 
Sad vigils, like a cloistered nun, 
Till his reviving ray appears, 
Waking her beauty as he dries her tears.” 
H 
