104 THE STORY OF THE PLANTS. 



so splendid for fertilisation that the plant is able 

 largely to reduce its number of stamens ; and 

 though it has three carpels, these are combined 

 at the base, thus showing the first step towards 

 a united ovary. 



I have treated the single family of the butter- 

 cups at some length, because I wished to show 

 you what sort of variations on a single plan 

 were common in nature. We see here a family, 

 built all on one scheme, but altering its archi- 

 tecture and decoration in the most singular 

 degree in its different members. The simplest 

 4 kinds are circular, symmetrical, orderly, and 

 yellow ; the highest are irregular, somewhat 

 strangely shaped, and blue or purple. This is 

 the general line of evolution in flowers. They 

 . begin like the buttercup ; they end like the 

 monkshood. 



Familiar instances of round or radial flowers, 

 consisting of separate petals, are the dog-rose, 

 the poppy, the mallow, and the herb-robert or 

 wild geranium. Most of these have five sepals 

 and five petals ; but in the poppy the petals are 

 usually reduced to four, and the sepals to two. 

 Again, a good instance of flowers with separate 

 petals which have become one-sided or irregular, 

 instead of circularly symmetrical, is afforded us 

 by the peaflowers, which include the pea, the 

 bean, the sweet-pea, the laburnum, the broom, 

 the gorse, the vetch, and the lupine. This 

 familiar family, known to botanists as the papi- 

 lionaceous or butterfly-like order (I trouble you 

 with as few long names as I can, so you must 



