86 THE COLOURS OF FLOWERS. 



of our British species from the norma of the race, has 

 a distinct tube to the corolla, and is blue or pink, 

 Asperula, which approaches nearer to the retrograde 

 Galiums, has one pale lilac species and one white. 

 The Galiums have no corolla-tube at all, and most of 

 them are white ; but two British species, G. verum and 

 G. cruciata, are yellow, and one of these has become 

 practically almost bi-sexual a common mark of 

 Retrogression. Rubia peregrina is even green. This 

 clearly marked instance of Retrogression from blue 

 through lilac and white to yellow makes the case of 

 the Composites easier to understand. No doubt the 

 dwarfed northern Stellates have found that they suc- 

 ceeded better by adapting themselves to the numerous 

 small insects of the fields and hedgerows, and there- 

 fore have fallen back upon the neutral colours, white 

 and yellow. 



Something the same explanation may be hazarded 

 in the case of the Umbelliferce, a difficult family to 

 deal with satisfactorily. It would be rash to assert 

 that these curious flowers are descended from mono- 

 petalous ancestors, yet, with the analogy of Galium 

 before our eyes, a suggestion to that effect may at 

 least be entertained as possible. The relations of the 

 Umbellifera with the Araliacece and Cornea are very 

 close ; and it is difficult to believe that the last named 

 family at least are not truly monopetalous. From 

 the Rubiacecz, indeed, a regular line of affinities leads 

 us on through Caprifoliacecz and Cornea to Umbelli- 

 fera ; and if we allow that Galium is descended from 

 a tubular form like Sherardia it is hard to draw a line 

 at such types as the elder, the wayfaring tree, the 

 dogwood, or the ivy, till we arrive at the true 



