294 



HUTCHINSON'S POPULAR BOTANY 



are beautifully simple. 



What is known as the "sleep" of plants in other 

 words, the nocturnal drooping and 

 folding of leaves and flowers com- 

 prehends the chief of those means, 

 and we shall here confine our re- 

 marks to this well-known phenome- 

 non. 



If you have ever sauntered 

 through a garden by night, and 

 examined, lantern in hand, the 

 dew-drenched vegetation, you will 

 have stumbled upon some curious 

 discoveries. It is easy to imagine 

 the surprise evoked during such 

 an excursion. As you pause before 

 one of the well-ordered beds, and 

 look down at the familiar plants, 

 you involuntarily ask yourself, 

 What has become of the flowers ? 

 A few, indeed, are still plainly visi- 

 ble ; but there are others that you 

 miss, nor do you realise what has 

 become of them until, on closer ex- 

 amination, you discover that some 

 are closed, and others are hanging 

 down their heads so that only their 

 green collars (the calyces) meet the 

 eye ; while others, again, have skil- 

 fully concealed themselves behind 

 their own foliage leaves. 



The leaves, too, appear to be 

 wonderfully changed. " We are 

 all a-noddin', nid-nid-noddin'," 

 seems to be their drowsy language. 

 The Tropoeolums no longer confront 

 the vault of heaven with their green 

 shields, which hang listless at their 

 sides ; the Lupins have folded up 

 their digitate leaves like umbrellas 

 (fig. 352) ; and on every hand the 

 foliage seems heavy with slumber. 



It may be cruel to unsettle so 



pleasing a fancy, but the phenomenon described, and which is popularly 

 known as the sleep of plants, is simply a part of Nature's plan for guarding 



Photo by] [E. Step. 



FIG. 359. OAK-WEED (Laminaria digitata), 



One of the largest of our native seaweeds. The specimens 

 photographed were fifteen feet long. 



