LAW OF PROGRESSIVE COLOURATION. 



35 



It is among the higher ranunculaceous plants, how- 

 ever, that we get the fullest and richest colouration. 

 Columbines [Aquilegia) are very specialised forms of 

 the buttercup type (Fig. lo). Both sepals and petals 



Fig. io.— Flower of columbine iAquiUgia vulgaris), with petals produced uito 

 honey-bearing spurs ; purple or blue. * — " 



are brightly coloured, while the former organs are pro- 

 duced above into long, bow-shaped spurs (i^ig. 1 1), each 

 of which se :retes a drop of honey. The carpels are also 



D 2 



