PLANTS THAT GO TO SLEEP 161 



The goafs-beard, sometimes known as "Go-to-bed- 

 at-noon," is so named on acount of its strange 

 custom of closing at that hour. The crocus often 

 closes up by noontime; and the oxalis will fall to 

 sleep, like a tired child, at various times of the day, 

 especially if the sun is shining on it; while other 

 plants, like the moonflower, the datura, and the 

 night-blooming cereus, sleep practically through- 

 out the entire day and come forth at night in all 

 their beauty ! 



These habits of opening and closing at different 

 times of the day and night are not only a protec- 

 tion against cold and heat, but also an assurance 

 that the plant will be ready to receive its welcome 

 guest, the pollen-bearing insect, whether he be a 

 toiler of the night or of the day; for instance, the 

 datura is visited only by insects of the night, and 

 if, for any reason, it opened its blossoms in the 

 day, it would possibly be neglected, and its flowers 

 left unfertilised. 



But plants require not only their daily sleep and 

 rest; they must have longer periods of undisturbed 

 quietude; in other words, they require vacations. 

 So plants hibernate, just as the chipmunk, the clever 

 arctic fox, and the arctic bear hibernate when the 

 cold weather approaches. And they are quite as 

 cunning and ingenious in providing for themselves 



