282 ADAPTATIONS AMONG ALPINE PLANTS 



to be observed towards evening. It is probable that 

 rapid changes in the illumination give the signal to 

 the plant to close its flowers or anthers, or to droop 

 the flower or flower-head. Atmospheric changes of 

 a marked nature are usually foreshadowed in the 

 Alps by some variation in the intensity of the 

 illumination. 



These special contrivances to prevent the flower 

 or the stamens becoming water-logged are extremely 

 interesting botanically, for they necessitate the move- 

 ment of one or more sets of organs. Yet, speaking 

 generally, the power of movement is as comparatively 

 rare among plants as it is common among animals. 

 Hence the mechanisms which efl'ect the opening and 

 closing of flowers and the like are of great importance, 

 though unfortunately it is not possible to enter into 

 the matter here in detail 



Seeds and Fruits. 



In the preceding chapters we have called attention 

 to some of the chief difficulties to be faced, as regards 

 climate, by plants living at high altitudes in Switzer- 

 land. It must not, however, be imagined that the 

 Alpine region, even with its manifold disadvantages, 

 is unsuited to support plant life. This is far from 

 being the case. The High Alps are extremely favour- 

 able to life, provided only that plants can adapt 

 themselves to the special conditions which there rule. 

 Early flowering and perennial existence are two of 

 the necessary conditions. Another is an abundance 



