742 



THE FLOKAL STEM. 



the form of small clouds of dust. In this instance the pollen is not only prevented 

 from being wasted by the spikate arrangement of the flowers, but this further ad- 

 vantage is obtained, that each flower shelters the pollen of the neighbouring flower 

 in a safe harbour until it can be transmitted by a favourable wind to its desired goal. 



Fig. 184. 



' Branch of the Walnut-tree (Juglans regia) with hanging male catkins, and a small cluster of female flowers; natural size 

 2 The tip of a male catkin ; enlarged. 



The grouping together of the flowers also offers numerous advantages with 

 regard to flower-visiting insects. Flies, bees, and humble-bees do not content them- 

 selves when seeking honey with taking it from single flowers, but climb from one 

 flower to another, from below up to the highest points of the spikes and racemes, 



