96 THE COLOURS OF FLOWERS. 



leads on to the very degenerate types of water- 

 plants. 



The Rosacece offer some good examples of green 

 flowers in which the petals have become quite extinct 

 Some of them are entomophilous, and some anemo- 

 philous. Alchemilla vulgaris (lady's mantle, Fig. 28) 

 is one of the former class. It is a degraded represen- 

 tative of the same group as agrimony ; but it has lost 

 its petals altogether. That it is a late, not a primitive 



FIG. 28. Flower of lady's mantle (Alchemilla), with double calyx, but no petals; 



green. 



form, is shown by its very reduced carpels, and its small 

 number of stamens. Alchemilla arvensis (parsley- 

 piert) is an extremely debased moss-like descendant 

 of some similar ancestor. It has tiny green petalless 

 axillary flowers, self-fertilised, but occasionally visited 

 by minute insects. Not far from these may be placed 

 Poterium sanguisorba (Fig. 29), another degraded 

 type, which has become anemophilous. This flower, 

 too, is green, and has no petals ; it usually possesses 

 but one carpel, and it is altogether a clearly 



