THE MICROSCOPE AND PLANT LIFE 



will cause these little balls to break and set free 

 a quantity of fine dust-like bodies called spores. 

 The spores will be carried about in the air, they are 

 so light, and if they settle on a suitable medium 

 they will germinate and start another growth of 

 mould. The blue-green mould of cheese is con- 

 structed quite differently; its spores are not con- 

 tained in any hollow structures like those of our 

 first object, but grow in chains radiating from a 

 central point, like the outstretched fingers of the 

 hand. It is this fungus, by the way, which imparts 

 the colour and flavour to gorgonzola cheese. 



For some reason living organisms, possessing the 

 power of movement, be it ever so slight, are always 

 more attractive than those which are apparently 

 motionless. Let us study two common objects from 



! the plant world which may easily be obtained by any 

 nature student, objects which owe their power of 

 movement — not to be confused with locomotion, by 



^ the way — to the presence or absence of moisture in 



; the air. On the under side of the fronds of many ferns 

 there will be found more or less rounded reddish- 

 brown spots. These outgrowths, for such they are, 



^ vary in position and shape according to the species 

 of fern. An examination, with a pocket lens, will 

 show that these brownish spots consist of minute 

 tufts of knobbed structures, growing from the tissues 

 of the frond. Sometimes the structures are naked, 

 sometimes covered with a membrane. In either 

 case, one or more of the knobbed structures is worth 



, examining under the microscope ; we shall then see 



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