LIFE HISTORIES OF FAMILIAR PLANTS 



When the flowering stem first appears amongst 

 the leaves, it also occupies the upper side of the 

 branch and stands erect, but as soon as its flowers 

 have matured sufficiently to invite the bees to pol- 

 linate them, the stalk bends over and elongates, 

 and so the raceme is suspended below the branch 

 where the fertilising insects are w^ell able to see 

 it. By doing this, however, the flowers become 

 placed upside down, i.e., the large overhanging 

 petal, or '^standard," becomes lowermost. This 

 difficulty is surmounted by each flower then twist- 

 ing half round on its stalk ; thus the flowers are 

 brought into their correct positions to receive the 

 fertilising bees. The laburnum has met its little diffi- 

 culties well, and has apparently made fairly smooth 

 progress throughout its development. 



Let us now endeavour to read the history of the 

 broom also by considering its structural details. 

 Why are its trifoliolate leaves so small ? Well, 

 the ancestral broom has, in the course of its history, 

 learned that on the hilly wastes and open places 

 where it makes its home, the production of large 

 leaves is a mistake, and means a waste of valuable 

 material. Indeed, it is trying its level best to do 

 without leaves altogether, in proof of which you 

 have its frequent tendency to produce leaves of 

 only one tiny leaflet. 



Those plants which develop leaves in such open 

 situations necessarily have to protect themselves 

 against the attacks of browsing animals ; thus we 

 find nettles, thistles, brambles, dog-roses, hawthorns, 

 blackthorns, and similar heath-loving species all 



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