LIFE HISTORIES OF FAMILIAR PLANTS 



plants of entirely different families, all of which 

 seem to have hit upon similar means of clustering 

 their minute flowers and thus, by their numbers, 

 competing with their neighbours bearing larger 

 blossoms. How well this purpose is effected is 

 readily appreciated by glancing at the flowers of 

 meadow-sweet, elder, lilac, and the large com- 

 pound umbels of the wild angehca (Fig. 112, Plate 

 81), and other members of its family. 



So it occurs that in the Pea-flower family, the 

 clovers, which bear the smallest flowers, have them 

 grouped into compact heads ; in the bird's-foot 

 trefoil and the kidney vetch they are arranged in 

 looser heads ; and in the true vetches and wild 

 peas, where the flowers are a little larger, we find 

 them, more or less, in closely arranged racemes, a 

 form of inflorescence that is well developed in the 

 laburnum. Finally, we have the larger flowers of 

 the family, as the broom and some of the peas, pro- 

 duced singly. Of course, no hard and fast line can 

 be drawn regarding this floral arrangement, 

 because exceptions occur in all branches of the 

 family ; it may, however, be applied in a general 

 way, for the exceptions can usually be accounted 

 for when their habits and environment are taken 

 into consideration. 



Now this grouping of the minute flowers into 

 showy heads tends to show that the clovers have 

 been considerably specialised and evolved. It 

 may be asked, however, why not view the matter 

 from the other side and say that the raceme of 

 flowers was evolved from the clover's compact 



152 



